The Eye

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The eye is a fused two-piece unit, The anterior (front) segment is made up of the cornea, iris and lens. The cornea is transparent and more curved, and is linked to the larger posterior segment, composed of the vitreous, retina, choroid and the outer white shell called the sclera. The cornea is typically about 12 mm in diameter, and 0.5 mm thick near its centre. The posterior (rear) chamber constitutes the remaining five-sixths; its diameter is typically about 24 mm. The iris is the circular pigmented area surrounding the centre of the eye, the pupil, which appears to be black. The size of the pupil, which controls the amount of light entering the eye, is adjusted by the iris' dilator and sphincter muscles.

Light energy enters the eye through the cornea, then the pupil and then the lens, before falling on the light-sensitive cells of the retina (photoreceptor cones and rods) that generate electrical signals that are transmitted to the brain by the optic nerve and interpreted as sight and vision. The lens shape is changed for near focus (accommodation) and is controlled by the ciliary muscle.

When the eye views an object far away, the rays of light entering the eye are parallel. The ciliary muscles and suspensory ligaments cause the lens to flatten. Conversely, when the object is close to the eye, the light enters at an angle and the muscles and ligaments allow the lens to fatten (convex) so the eye can focus on the close object. When the eye is unable to adjust the lens shape sufficiently, then glasses can be worn to correct the focus.

There are six extraocular muscles that control eye movements. By having two eyes, stereo vision, animals are able to judge distance to objects.

The Ear

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The ear is the organ that enables hearing and, in mammals, body balance using the vestibular system. In mammals, the ear is usually described as having three parts — the outer ear, the middle ear and the inner ear. The outer ear consists of the pinna and the ear canal. Since the outer ear is the only visible portion of the ear in most animals, the word "ear" often refers to the external part alone. The middle ear includes the tympanic cavity and the three ossicles. The inner ear sits in the bony labyrinth, and contains structures which are key to several senses: the semicircular canals, which enable balance and eye tracking when moving; the utricle and saccule, which enable balance when stationary; and the cochlea, which enables hearing. The ears of vertebrates are placed somewhat symmetrically on either side of the head, an arrangement that aids sound localisation.

The ear develops from the first pharyngeal pouch and six small swellings that develop in the early embryo called otic placodes, which are derived from ectoderm.

The ear has been adorned by earrings and other jewelry in numerous cultures for thousands of years, and has been subjected to surgical and cosmetic alterations.

The ear may be affected by disease, including infection and traumatic damage. Diseases of the ear may lead to hearing loss, tinnitus and balance disorders such as vertigo, although many of these conditions may also be affected by damage to the brain or neural pathways leading from the ear.

The Heart

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The heart is an organ that pumps blood throughout the body via the circulatory system, supplying oxygen and nutrients to muscles and tissues and removing carbon dioxide and other waste products.

The heart is a muscle, about the size of your fist, in the middle of your chest tilted slightly to the left. Each day your heart beats around 100,000 times, circulating about five litres (eight pints) of blood. Replenished blood is distributed through a network of arteries, returning through a complementary network of veins. In between are tiny capillaries with very thin walls, which allow them to exchange compounds (such as oxygen and carbon dioxide, water, nutrients and waste) with surrounding tissues. Waste products are removed from the blood in the kidneys.

The right side of the heart receives deoxygenated blood and sends it to the lungs, which remove the carbon dioxide and replenish with oxygen. The left side receives blood from the lungs and pumps it to all parts of the body. Arteries are strong and their elastic walls help keep blood pressure consistent. Veins have thinner walls than arteries.

When exercising, the heart beats faster to get oxygen and nutrients to the muscles, increasing from an idling rate of 60 beats per minute to almost 200 bpm. The heart can take strain without you being aware of it. Over a long period of time your diet can influence the condition of your blood vessels and valves of the heart. Monitoring blood pressure is essential to know the condition of your circulatory system.

Human Digestive System

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Your digestive system turns the food you eat into nutrients, which the body uses for energy, growth and cell repair. The digestion process starts in your mouth. Biting and chewing breaks the food into pieces that are more easily digested, while saliva mixes with food to begin the process of breaking it down into a form your body can absorb and use.

The throat (pharynx) is a muscular valve that controls airflow into the lungs and directs solids and liquids towards the stomach through the oesophagus.

The oesophagus is a muscular tube extending from the throat to the stomach. The oesophagus delivers food to the stomach through a series of contractions, called peristalsis. Just before the connection to the stomach, there is a "zone of high pressure", called the lower oesophageal sphincter which prevents food from passing back into the oesophagus.

The stomach is a sac-like organ with strong muscular walls. In addition to holding the food, it's also a mixer and grinder. The stomach secretes acid and powerful enzymes that continue the process of breaking down the food. When it leaves the stomach, food is the consistency of a liquid or paste. From there, the food moves to the small intestine.

The liver filters the blood coming from the digestive tract before it passes to the rest of the body. The liver also detoxifies chemicals and metabolises drugs. The liver secretes bile via the gallbladder back to the intestines.

The pancreas plays an essential role in converting the food we eat into fuel for the body's cells. It has two main functions—the exocrine function that helps digestion, and a vital endocrine function that regulates blood sugar.

The small intestine is a 6m long tube, loosely coiled in the abdomen, made up of three segments, the duodenum, jejunum, and ileum. The small intestine continues the process of breaking down food using segmentation (bi-directional peristaltic contractions) and enzymes released by the pancreas and bile from the liver. Bile aids in the digestion of fat and eliminates waste products from the blood. The duodenum is mainly responsible for breaking down food, with the jejunum and ileum being mainly responsible for the absorption of nutrients into the bloodstream.

The final stage of the journey for solids is through the large intestine to the rectum for final discharge through the anus.

Human Nervous System

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The nervous system is a sophisticated collection of nerves and specialised cells called neurons that transmit signals between different parts of the body. It is essentially the body's electrical wiring.

The brain and spinal cord together form the central nervous system; all the other nerves in the body are the peripheral nervous system. The nerves themselves are cylindrical bundles of fibres.

The brain is the central computer of the nervous system. It receives messages from the body, processes the information, and sends signals back to tell the body how to respond. The spinal cord is the main information highway of the nervous system and connects the brain to all the nerves that help you sense the world.

The peripheral nervous system includes sensory nerves that receive information from your sensory organs (your eyes, ears, nose, tongue and skin) and motor nerves that carry information to muscles throughout your body. There are many other kinds of nerves in the peripheral nervous system that have special functions for communicating with your internal organs (e.g. heart, lungs and liver.)

Neurons send signals to other cells through thin fibres called axons, which cause chemicals known as neurotransmitters to be released at junctions called synapses. There are 86 billion neural connections in the average human brain.

Human Muscles

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Muscles are a type of soft tissue found in humans and most animals. Muscles allow us to consciously move our limbs so we can jump in the air, chew our food and perform other conscious actions. They are also responsible for many sub-conscious processes, such as keeping our hearts pumping, moving food through our guts, and even making us blush.

Our muscles need signals from our brains and energy from our food to contract and move. There are two types of muscles. Striated muscles consist of multiple fibres arranged in parallel, whereas smooth muscles have interconnected cells that form layers.

The skeletal muscles that move our body parts are striated muscles, and we actively control these with our brain. We are not able to control all the striated muscles, like those that keep our hearts pumping. These muscles work on their own without us even thinking about it.

Specific molecules within the muscle fibres, particularly actin and myosin, allow striated muscles to contract rapidly, allowing us to move. The energy for muscles comes from the food that we eat.

The contractions that smooth muscles produce tend to be more gradual than those produced by striated muscle. An example is the slow and controlled movement of food through the digestive system.

Although the pathways that regulate contraction in striated and smooth muscles are very different, calcium is the common key molecular messenger in the process.

Striated muscles receive their triggers from the brain via motor neurons, whereas smooth muscle cells are activated by neuronal signalling or by hormones. This results in calcium rushing into the muscle, activating the actin and myosin and causing the muscle to contract.

Some smooth muscles are in a permanent state of contraction, and the muscles that line our blood vessels are in this category. A constant supply of calcium allows these muscles to regulate blood flow. For example, when the muscles that line the blood vessels in our face relax, we blush.

Human Skeleton

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The skeletal system includes all the bones and joints in the body. Each bone is a complex living organ made up of many cells, protein fibres, and minerals. The skeleton provides support and protection (skull and ribs) for the soft organs that make up the rest of the body. The bones have attachment points for muscles and tendons to allow movements at the joints. The red bone marrow produces new blood cells inside of our bones. Bones act as the body’s warehouse.

The skeletal system in an adult body is made up of 206 individual bones arranged into two major divisions:
• The axial skeleton (80 bones) runs along the body’s vertical axis and includes the skull, ribs, sternum, and vertebral column.
• The appendicular skeleton (126 bones) makes up the limbs, the shoulder, and pelvic girdles.

The skeleton makes up about 30-40% of an adult’s body mass and consists of non-living bone matrix and many tiny bone cells. Roughly half of the bone mass is water, while the other half is collagen protein and solid crystals of calcium carbonate and calcium phosphate.

Living bone cells are found on the surfaces of bones and in small cavities inside the bone matrix. Although these cells make up very little of the total bone mass, they are essential for bone growth and repair during daily wear and injury.

The bone matrix is our calcium bank, storing and releasing calcium ions into the blood as needed for the proper function of the nervous and muscular systems. Red bone marrow is found in the hollow space inside of bones known as the medullary cavity and produces red and white blood cells in a process known as haematopoiesis. Red bone marrow also stores iron used to form haemoglobin in red blood cells.

Five Basic Senses

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Humans have five basic senses: touch, sight, hearing, smell and taste. The sensory organs (skin, eyes, ears, nose and tongue) send information to the brain to help us perceive the world around us.

For touch, several distinct sensations in the skin are communicated to the brain through specialized neurons.

For sight, light passes through the lens of an eye. It is focussed onto the retina where photoreceptors called rods (for black and white) and cones (for colour) convert the information into electrical impulses sent to the brain. The iris (coloured part of the eye) controls how much light enters the eye.

For hearing, sound waves pass from the outer ear, through the auditory canal and onto the eardrum. In the middle ear, delicate bones transfer the vibrations to fine hairs in the inner ear, which produce electrical signals that the brain decodes as sound.

For smell, there are millions of nerve endings in the olfactory cleft in the roof of the nasal cavity, that transmit complex smell information directly to the brain. The number of unique smell combinations is almost infinite.

For taste, receptors around our tongue, the roof of the mouth and throat detect the four primary tastes: salty, sweet, sour and bitter. Recently a fifth taste, umami (or savoury) has been added.

The Sun

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The Sun is the star at the centre of our Solar System. It is by far the most important source of energy for life on Earth. The interactions between the Sun and Earth drive the seasons, ocean currents, weather, climate and calendar.

The Sun is 75% hydrogen and 25% helium. It’s energy comes from the fusion of hydrogen into helium. Its diameter is about 1.39 million kilometres (864 000 miles), or 109 times that of Earth, and its mass is about 330,000 times that of Earth.

The Sun currently fuses about 600 million tons of hydrogen into helium every second, converting 4 million tons of matter into energy every second producing light and heat. It takes light just over 8 minutes to travel the 150 000 000 km (93 000 000 miles) from sun to earth. Of the approximately 1 500 W/m2 of energy that reaches earth only 1 000 W/m2 reaches the ground.

Our sun’s class and size make it a yellow dwarf star. It formed approximately 4.6 billion years ago. It accounts for about 99.86% of the total mass of our solar system. The rest flattened into an orbiting disk from which the planets formed. The sun’s gravity holds our solar system together, keeping everything from the biggest planets to the smallest particles of debris in its orbit.

Electric currents in the Sun generate a magnetic field that is carried out through the solar system by the solar wind—a stream of electrically charged gas blowing outward from the Sun in all directions.

There are billions of stars like our Sun in just our Milky Way galaxy alone.

Wind Turbines

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Wind turbines produce electricity from the energy of the wind. Quite simply the wind turns a propeller, which spins a generator that creates electricity.

Wind is a renewable energy source, deriving energy from the weather (caused by the sun). Early examples were mechanical windmills for grinding flour, using sails made from fabric on wooden frames.

Modern wind turbines use aerodynamic blades, which work like an aeroplane wing or helicopter rotor blade. When wind flows across the blade, the air pressure on one surface of the blade increases. The difference in air pressure across the two surfaces of the blade causes the rotor to spin. The rotor is connected, through a gearbox, to an electric generator that produces electricity.

The whole wind turbine itself can be turned on top of its mast so that it can face the wind. When the wind is too strong the turbine can be turned out of the wind and a brake applied to prevent the rotor from turning.

Fungi

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Fungi are all around us, in the soil, our bodies and the air, but are often too small to be seen with the naked eye. There are 120,000 classified types of fungi. Scientists estimate that there are 2.2 – 3.8 million species in total, including mushrooms, yeast, lichens, rust, and mold.

Fungi are non-motile, heterotrophic (no chlorophyll), unicellular (yeast) or filamentous (fungus), reproduce by means of spores, consist of long thread-like structures known as hyphae that form a mesh-like structure called mycelium.

Some play an important role in the decomposition of organic material and nutrient cycling in nature, while others form symbiotic relationships with plants. Others are plant or animal pathogens or endophytes (living inside a plant). They also serve as a food source for a large variety of organisms, including humans.

They occur in most habitats from the Arctic to Antarctica, from high mountain tops to desert sand. Some even lives in marine and fresh water environments. More than 90% of the estimated 3.8 million fungi in the world are currently unknown to science.

Did you know?
1. A fungus lives in symbioses with algae and this beneficial lifeform is called a lichen.
2. Fungi are in a kingdom of their own but are closer to animals than plants.
3. They have chemicals in their cell walls shared with lobsters and crabs.
4. There is evidence to suggest that yeasts - a type of fungus - were being used to produce the alcoholic drink mead as long ago as 9,000 years ago.
5. Products made from fungi can be used as replacements for polystyrene foam, leather and building materials.
6. DNA studies show that there are thousands of different fungi in a single sample of soil, many of which are unknown and hidden.
7. They are 2-10µm in size.
8. A huge underground fungus that is one of the largest living organisms on the planet. It spanned at least 0.37 square kilometres .It was estimated in 1980 to be at least 1500 years old and weighed at least 100,000 kilograms.
9. Fungi affects every part of your life, what you eat, what you wear, what you do and your mood.
10. Mycorrhizal fungus forms an essential symbiotic relationship with plant roots. Mycorrhizal fungi help tree and shrub roots find water and nutrients. In return, the roots give the fungi carbon, carbohydrates, and other nutrients.
11. Mushrooms and other fungi release an incredible amount of spores into the atmosphere every year, and contributing up to 50 million tonnes of particulates.

Photovoltaic Energy

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Photovoltaics (PV) are special semiconducting materials that convert light into electricity. They have gained in popularity as their efficiency and reliability have increased and the cost of manufacture has decreased. From small localised systems they are now viable to provide power into the national grid.

A PV system for the grid requires millions of panels, each comprising hundreds of solar cells. The PV panels can be mounted on the ground, rooftops, walls or even floating. The mounts may be fixed, in which case their output will vary as the sun moves, or use a solar tracker to follow the sun. A single PV cell only produces about 0.5V so they are assembled and arranged in series and in parallel to get the desired voltage and current output. They produce direct current electricity and require large powerful inverters to produce electricity for the grid.

Solar PV has specific advantages as an energy source: once installed, it produces no pollution and no greenhouse gas emission; it is very modular to satisfy power needs and silicon is abundant in the Earth's crust.

Photovoltaic systems have been used (since 1950s) in specialized stand-alone applications, notably satellites in space. Grid-connected PV systems have been in use since the 1990s.

More than 100 countries now use solar PV. In terms of global capacity PV is currently the third renewable energy source, after hydro and wind. In 2018, world-wide installed PV capacity increased to more than 515 gigawatts (GW) providing approximately two percent of global electricity demand.

Telescope

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Telescopes stand as humanity's windows to the cosmos, offering unparalleled glimpses into the vast expanse of space and the wonders it holds. This educational journey delves into the realms of optics, astronomy, celestial objects, space exploration, and the rich history of telescopes, illuminating the fascinating intersection of science, technology, and human curiosity.

At the heart of the telescope's marvel lies the science of optics, which explores the behaviour of light and its interaction with lenses and mirrors. Telescopes harness the principles of optics to collect and focus light from distant celestial objects, enabling astronomers to observe and study them in detail. Through the careful design and construction of lenses, mirrors, and other optical components, telescopes magnify faint and distant objects, unveiling the secrets of the universe.

Astronomy, the study of celestial objects and phenomena beyond Earth's atmosphere, is intrinsically linked to the telescope's capabilities. Telescopes serve as indispensable tools for astronomers, allowing them to explore the cosmos across a broad range of wavelengths, from visible light to radio waves, X-rays, and beyond. By observing stars, galaxies, nebulae, and other cosmic entities, astronomers unravel the mysteries of the universe, probing its origins, evolution, and ultimate fate.

The history of telescopes is a testament to human ingenuity and the quest for understanding the cosmos. From the humble beginnings of early optical devices, such as the refracting telescope invented by Dutch spectacle maker Hans Lippershey in the early 17th century, to the cutting-edge technologies of modern observatories like the Hubble Space Telescope, telescopes have undergone remarkable advancements over the centuries. Each milestone in telescope development has expanded our view of the universe and revolutionized our understanding of the cosmos.

Telescopes have played pivotal roles in space exploration, providing vital data and imagery for missions to study planets, moons, asteroids, comets, and other celestial bodies. Space telescopes, like the Hubble Space Telescope and the James Webb Space Telescope, offer unparalleled views of the universe from beyond Earth's atmosphere, free from the distorting effects of the atmosphere.

Lungs

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Human lungs are remarkable organs responsible for the crucial task of breathing, which provides oxygen to the body's cells and removes carbon dioxide, a waste product of metabolism. Each person has two lungs, situated in the chest cavity on either side of the heart. The lungs are spongy in texture and pinkish in color, resembling two large air-filled balloons.

The lungs are divided into sections called lobes – three on the right lung and two on the left. Inside the lungs are a vast network of airways, including the trachea (windpipe), bronchi, and bronchioles, which branch out like tree limbs and end in small air sacs called alveoli. It is within these alveoli that the exchange of gases occurs: oxygen from the air enters the bloodstream, while carbon dioxide from the bloodstream exits the body when we exhale.

The process of breathing, also known as respiration, is controlled by the respiratory system, which includes the lungs, airways, and muscles involved in breathing. When we inhale, the diaphragm – a dome-shaped muscle beneath the lungs – contracts and moves downward, creating space for the lungs to expand. This allows air to rush into the lungs. When we exhale, the diaphragm relaxes, and the lungs recoil, pushing air out of the body.

Human lungs are essential for survival, as they enable the body to receive the oxygen it needs to function properly. Maintaining lung health is crucial for overall well-being, and practices such as regular exercise, avoiding smoking and pollution, and maintaining a healthy diet can help support lung function.

Kidneys

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Human kidneys are vital organs responsible for filtering waste products and excess fluids from the bloodstream to produce urine. Each person has two kidneys, located on either side of the spine, just below the rib cage. The kidneys are bean-shaped organs, reddish-brown in color, and about the size of a fist.

The main function of the kidneys is to remove waste products, such as urea and creatinine, from the blood and excrete them in the form of urine. Additionally, the kidneys regulate the body's fluid balance, electrolyte levels, and blood pressure by adjusting the concentration and volume of urine produced.

Inside each kidney are tiny structures called nephrons, which are responsible for the filtration and purification of blood. Each nephron consists of a filtering unit called the glomerulus, surrounded by a tubule. As blood passes through the glomerulus, waste products and excess fluids are filtered out and collected in the tubule, while essential substances such as water, electrolytes, and glucose are reabsorbed back into the bloodstream.

The kidneys also play a crucial role in the production of hormones that regulate various bodily functions. For example, they produce erythropoietin, which stimulates the production of red blood cells, and renin, which helps regulate blood pressure.

Maintaining kidney health is essential for overall well-being, as kidney dysfunction can lead to serious health problems, including kidney disease, kidney stones, and electrolyte imbalances. Practices such as staying hydrated, maintaining a healthy diet, and avoiding excessive consumption of alcohol and certain medications can help support kidney function..

Liver

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The human liver is a vital organ with multiple functions essential for maintaining overall health and well-being. It is the largest internal organ in the body and is located in the upper right side of the abdomen, just below the diaphragm. The liver is reddish-brown in color and has a soft, spongy texture.

One of the liver's primary functions is to filter and detoxify blood coming from the digestive tract before it circulates throughout the rest of the body. It removes harmful substances such as toxins, drugs, and alcohol from the bloodstream, converting them into less harmful compounds that can be excreted from the body.

The liver also plays a crucial role in metabolism, the process by which the body converts food into energy. It helps regulate blood sugar levels by storing glucose as glycogen and releasing it into the bloodstream when needed. Additionally, the liver synthesizes proteins necessary for blood clotting, immune function, and transport of nutrients throughout the body.

Another important function of the liver is the production of bile, a greenish-yellow fluid that helps digest fats in the small intestine. Bile is produced in the liver and stored in the gallbladder until it is needed for digestion. The liver continuously produces bile to aid in the digestion and absorption of fats from the diet.

Maintaining liver health is crucial for overall well-being, as liver dysfunction can lead to serious health problems, including liver disease, hepatitis, and liver cancer. Practices such as maintaining a healthy diet, limiting alcohol consumption, and avoiding exposure to toxins can help support liver function and prevent liver-related complications.

Mercury

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Mercury, the closest planet to the Sun, is a fascinating world of extremes. It's the smallest planet in our solar system, with a diameter just a bit larger than Earth's Moon. Despite its diminutive size, Mercury is a fiery planet, experiencing temperatures that range from scorching hot to freezing cold. During the day, when Mercury faces the Sun, temperatures can soar up to a blistering 800 degrees Fahrenheit (430 degrees Celsius). However, at night, when Mercury turns away from the Sun, temperatures plummet to a bone-chilling minus 290 degrees Fahrenheit (minus 180 degrees Celsius).

Mercury is a rocky planet with a heavily cratered surface, resembling the surface of Earth's Moon. Its surface features include vast plains, towering cliffs, and deep craters formed by impacts from asteroids and comets. The planet's lack of atmosphere means there is no protection from these impacts or from the Sun's intense radiation.

Despite its proximity to the Sun, Mercury is not the hottest planet in our solar system. That title goes to Venus, the second planet from the Sun. However, Mercury does have the greatest temperature variation between its day and night sides, making it one of the most extreme environments in our solar system.

Venus

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Venus, often called Earth's "twin" due to its similar size and composition, is a mysterious and inhospitable world. It is the second planet from the Sun and is often referred to as the "morning star" or the "evening star" because it is one of the brightest objects in the night sky. Despite its beauty when viewed from Earth, Venus is a hostile planet with surface temperatures hot enough to melt lead.

The surface of Venus is shrouded in thick clouds of sulfuric acid, making it impossible to see the planet's surface with the naked eye. These clouds trap heat from the Sun, creating a runaway greenhouse effect that has caused Venus to become the hottest planet in our solar system, even hotter than Mercury.

Beneath its toxic atmosphere, Venus has a rocky surface with vast plains, towering mountains, and deep valleys. It is home to numerous volcanoes, including the massive Maxwell Montes, which is the highest mountain on Venus. The planet's surface is littered with volcanic features, indicating a history of volcanic activity.

Despite its extreme conditions, scientists are intrigued by Venus and continue to study its atmosphere and surface using spacecraft and telescopes. Understanding Venus could provide valuable insights into the processes that shape rocky planets and help scientists better understand the potential for life beyond Earth.

Earth

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Earth, our home planet, is a unique and vibrant world teeming with life. It is the third planet from the Sun and the only planet in our solar system known to support life. Earth's surface is covered in vast oceans, lush forests, towering mountains, and sprawling deserts, creating a diverse and dynamic environment.

One of the most remarkable features of Earth is its atmosphere, which is composed primarily of nitrogen and oxygen. This atmosphere acts as a protective shield, filtering out harmful solar radiation and regulating the planet's temperature. Earth's atmosphere also plays a crucial role in the water cycle, weather patterns, and climate regulation.

The surface of Earth is divided into several major landmasses, including continents and islands, which are surrounded by vast oceans. These landmasses are constantly shifting and changing due to processes like plate tectonics and erosion, shaping the planet's landscape over millions of years.

Earth is also home to a staggering array of life forms, from microscopic bacteria to towering trees and majestic animals. The diversity of life on Earth is unparalleled, with millions of species inhabiting every corner of the planet, from the depths of the ocean to the highest mountains.

In addition to its natural beauty and biodiversity, Earth is also unique in its ability to sustain life. The presence of liquid water, moderate temperatures, and a stable atmosphere make Earth the perfect habitat for a wide variety of organisms, including humans. Protecting and preserving Earth's delicate balance is essential for the continued survival of life on our planet.

The Moon

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The Moon, Earth's only natural satellite, is a fascinating and mysterious world that has captivated humans for thousands of years. It orbits around Earth at a distance of about 238,855 miles (384,400 kilometers) and is about one-quarter the size of Earth. The Moon has a rocky surface covered in craters, mountains, and plains, with no atmosphere to protect it from meteoroids and solar radiation.

One of the most striking features of the Moon is its phases, which change as it orbits around Earth. These phases, from a full moon to a new moon and back again, are caused by the relative positions of the Moon, Earth, and Sun. The Moon's gravity also affects Earth's tides, causing them to rise and fall in a predictable pattern.

The Moon has played a crucial role in human history and culture, inspiring myths, legends, and scientific inquiry. It has been the target of numerous spacecraft and missions, including the Apollo missions, which brought humans to the lunar surface for the first time. Today, the Moon continues to be a focus of scientific research and exploration, with plans for future missions to return humans to the lunar surface and establish a permanent presence there.

Mars

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Mars, often called the "Red Planet" due to its rusty hue, is a cold and barren world with a fascinating history. It is the fourth planet from the Sun and is about half the size of Earth. Mars has intrigued scientists for centuries with its potential for harboring life and its similarities to Earth.

The surface of Mars is covered in reddish-brown soil and is dotted with impact craters, volcanoes, and vast plains. One of the most prominent features of Mars is Olympus Mons, the largest volcano in the solar system, which stands nearly three times taller than Mount Everest. Mars also has a massive canyon system called Valles Marineris, which stretches for over 2,500 miles (4,000 kilometers) and is deeper than the Grand Canyon.

Despite its barren appearance, Mars has captured the imagination of scientists and explorers alike. Evidence from spacecraft and rovers suggests that Mars was once a warmer and wetter planet with rivers, lakes, and possibly even oceans. Scientists continue to search for signs of past or present life on Mars, studying its geology, atmosphere, and climate to unravel the planet's mysteries.

In recent years, Mars has become a focus of human exploration, with numerous missions planned to study the planet and prepare for future human missions. NASA's Perseverance rover, launched in 2020, is currently exploring the surface of Mars, searching for signs of ancient microbial life and collecting samples for return to Earth. The exploration of Mars holds the promise of answering fundamental questions about the potential for life beyond Earth and the future of human space exploration.

Jupiter

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Jupiter, the largest planet in our solar system, is a gas giant with a mesmerizing appearance and a host of fascinating features. It is the fifth planet from the Sun and is more than twice as massive as all the other planets combined. Jupiter's massive size and strong gravitational pull make it a dominant force in the solar system, influencing the orbits of nearby objects and protecting the inner planets from potential impacts.

One of the most striking features of Jupiter is its colorful bands of clouds, which are made up of ammonia crystals and other compounds. These bands of clouds swirl around the planet, creating mesmerizing patterns and storms that can last for centuries. The most famous of these storms is the Great Red Spot, a massive storm system that has been raging for over 300 years and is larger than Earth itself.

Beneath its thick atmosphere, Jupiter has a core made of rock and metal surrounded by layers of hydrogen and helium gas. Despite its massive size, Jupiter has no solid surface, so if you were to try to land on the planet, you would simply fall through its atmosphere until you reached its core.

Jupiter is also home to a diverse array of moons, with over 70 known moons orbiting the planet. The four largest moons – Io, Europa, Ganymede, and Callisto – are known as the Galilean moons and were discovered by the astronomer Galileo Galilei in 1610. These moons are each unique worlds with their own geology and atmosphere, and they continue to fascinate scientists with their potential for harboring life.

Saturn

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Saturn, known for its majestic rings, is the sixth planet from the Sun and the second largest in our solar system. It is a gas giant like Jupiter, composed mostly of hydrogen and helium, with a small rocky core at its center. Saturn's most distinctive feature is its rings, which are made up of billions of icy particles ranging in size from tiny grains to large chunks. These rings extend thousands of kilometers from the planet's surface and are visible even from Earth with a small telescope.

Beneath its rings, Saturn has a thick atmosphere with colorful bands of clouds, similar to Jupiter. The planet's atmosphere is primarily composed of hydrogen and helium, with traces of other gases like methane and ammonia. Saturn's atmosphere is also home to powerful storms, including a hexagonal-shaped storm near its north pole.

Saturn has a diverse collection of moons, with over 80 known moons orbiting the planet. The largest of these moons is Titan, which is larger than the planet Mercury and is the only moon in the solar system with a dense atmosphere. Titan's atmosphere is primarily composed of nitrogen, with traces of methane and other gases, making it an intriguing target for future exploration.

In addition to Titan, Saturn's moons include Enceladus, which has geysers of water vapor erupting from its surface, and Mimas, which has a large crater resembling the "Death Star" from Star Wars. These moons, along with Saturn's rings, make it one of the most captivating objects in the night sky.

Uranus

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Uranus, the seventh planet from the Sun, is an ice giant with a mysterious and enigmatic atmosphere. It is the third largest planet in our solar system and is tilted on its side, with its axis of rotation nearly parallel to its orbit around the Sun. This unique orientation gives Uranus its distinctive appearance and causes extreme seasonal variations as it orbits the Sun.

Uranus has a thick atmosphere composed primarily of hydrogen and helium, with traces of methane that give it a blue-green color. The planet's atmosphere is marked by high-speed winds that can reach speeds of up to 560 miles per hour (900 kilometers per hour). Uranus also has a system of faint rings and a collection of moons, the largest of which is named Titania.

Despite its unique features, Uranus is one of the least explored planets in our solar system, with only one spacecraft – Voyager 2 – having visited the planet in 1986. The limited data collected by Voyager 2 has left many questions unanswered, including the origin of Uranus' unusual tilt and the composition of its atmosphere. Future missions to Uranus could provide valuable insights into the history and evolution of our solar system.

Neptune

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Neptune, the eighth and farthest planet from the Sun, is a frigid and distant world with a dynamic and turbulent atmosphere. It is the fourth largest planet in our solar system and is composed primarily of hydrogen and helium, with traces of methane that give it a blue color. Neptune's atmosphere is marked by powerful storms, including the Great Dark Spot – a massive storm system similar to Jupiter's Great Red Spot.

Neptune has a system of faint rings and a collection of moons, the largest of which is named Triton. Triton is unique among Neptune's moons because it orbits the planet in a retrograde direction, opposite to the planet's rotation. Triton is also one of the coldest objects in our solar system, with surface temperatures that can plunge to minus 391 degrees Fahrenheit (minus 235 degrees Celsius).

Despite its remote location, Neptune has been visited by only one spacecraft – Voyager 2 – which flew by the planet in 1989. Voyager 2 provided valuable data about Neptune's atmosphere, rings, and moons, but many questions remain unanswered. Future missions to Neptune could provide insights into the planet's composition, weather patterns, and geological features.

The Milky Way

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The Milky Way, our home galaxy, is a vast and majestic cosmic structure that stretches across the night sky like a shimmering river of stars. Named for its hazy appearance as seen from Earth, the Milky Way is a spiral galaxy composed of billions of stars, stellar remnants, gas, and dust, bound together by gravity.

At the heart of the Milky Way lies a dense region known as the galactic bulge, where stars are densely packed and stellar densities are highest. Surrounding the bulge is a flattened disk of stars, gas, and dust, which extends outward in a spiral pattern. Spiralling arms of stars and interstellar material spiral outwards from the central bulge, creating the iconic spiral arms that give the galaxy its distinctive appearance.

Our solar system resides in one of the Milky Way's spiral arms, known as the Orion Arm or Local Spur. From our vantage point within the galaxy, we peer outward into the vast expanse of space, observing the stars, nebulae, and other celestial objects that populate our cosmic neighbourhood.

The Milky Way is a dynamic and evolving entity, with stars orbiting the galactic centre in elliptical, circular, and spiral trajectories. Over billions of years, these stars interact with one another, forming stellar clusters, binary systems, and occasionally, catastrophic events such as supernovae and black hole mergers.

Moreover, the Milky Way is not alone in the cosmos but is part of a larger cosmic web of galaxies, clusters, and superclusters, bound together by the force of gravity. As we peer deeper into space with telescopes and observatories, we uncover the vastness of the universe and our place within it.

Studying the Milky Way provides insights into the formation, evolution, and dynamics of galaxies, shedding light on the processes that shape the cosmos. It allows us to probe the mysteries of dark matter and dark energy, understand the origins of stars and planets, and explore the potential for life beyond Earth.

Our Galaxy

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Our galaxy, known as the Milky Way, is a spectacular celestial phenomenon that enchants observers with its vastness and beauty. It spans an immense distance of about 100,000 light-years and comprises billions of stars, along with interstellar gas and dust. A stunning spiral galaxy, the Milky Way boasts a mesmerising structure, with a central bulge surrounded by a flattened disk of stars, gas, and dust. Radiating outwards from the bulge are magnificent spiral arms, each adorned with stellar clusters, nebulae, and other celestial wonders.

Nestled within one of these spiral arms, our solar system finds its home. From our position within the galaxy, we are afforded a breathtaking view of the cosmos, as we peer into the depths of space and marvel at the myriad stars and galaxies that populate our galactic neighbourhood.

The Milky Way is a dynamic and ever-evolving entity, with stars tracing graceful orbits around its centre. Over eons of time, these stars interact, forming clusters, binary systems, and occasionally experiencing cataclysmic events such as supernovae and black hole mergers.

Furthermore, the Milky Way is not an isolated entity but rather part of a vast cosmic ensemble, bound together by the force of gravity. As we explore the universe with increasingly powerful telescopes and instruments, we gain insights into the interconnectedness of galaxies and the intricate tapestry of the cosmos.

Studying our galaxy opens a window into the mysteries of the universe, offering clues about its origins, evolution, and ultimate fate. It allows us to ponder the enigmatic phenomena of dark matter and dark energy, contemplate the formation of stars and planets, and speculate about the possibility of life beyond our solar system.

In conclusion, the Milky Way stands as a testament to the grandeur and complexity of the universe, inspiring wonder and curiosity in all who contemplate its splendour. By studying our galaxy, we embark on a journey of discovery, deepening our understanding of the cosmos and our place within it.

Plants (plant biodiversity /categorisation)

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Plants are an integral component of our planet's ecosystem, playing a vital role in sustaining life as we know it. From the towering trees of the Amazon rainforest to the delicate wildflowers of the British countryside, plant life encompasses an astonishing array of forms, functions, and adaptations. Understanding plant biodiversity and categorisation is essential for appreciating the complexity and beauty of the natural world.

Plant biodiversity refers to the rich variety of plant species coexisting in different environments around the globe. It encompasses not only the vast array of species but also their genetic diversity within each species. This diversity ensures resilience and adaptability in the face of environmental changes, making it crucial for the health and stability of ecosystems.

Scientists categorise plants into various groups based on shared characteristics, allowing us to organise and understand this diversity more effectively. One of the primary classifications divides plants into flowering plants (angiosperms) and non-flowering plants (gymnosperms and ferns). Flowering plants, the most diverse group, produce seeds enclosed within fruits and flowers and dominate terrestrial ecosystems worldwide. Non-flowering plants include gymnosperms, such as conifers and cycads, which bear seeds in cones, and ferns, which reproduce via spores.

Beyond these broad categories, plants are further classified into smaller groups based on characteristics such as leaf structure, reproductive methods, and evolutionary relationships. Mosses, liverworts, and algae represent additional groups, each with distinct adaptations enabling them to thrive in specific habitats and environmental conditions.

Studying plant biodiversity and categorisation provides valuable insights into ecosystem dynamics, species interactions, and environmental changes over time. It helps scientists monitor shifts in plant populations, track the impacts of human activities such as deforestation and climate change, and identify areas of conservation priority.

Moreover, understanding plant diversity enriches our appreciation of the natural world and fosters a sense of stewardship for the environment. It inspires curiosity and wonder, encouraging individuals of all ages to explore and connect with the plants that surround them.

Photosynthesis

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Photosynthesis is one of the most fundamental processes in nature, driving the conversion of light energy into chemical energy and supporting life on Earth. This remarkable biochemical process occurs in the chloroplasts of plant cells, where chlorophyll, the green pigment, captures sunlight and initiates a series of complex reactions.

During photosynthesis, plants absorb carbon dioxide (CO2) from the atmosphere through tiny pores called stomata on their leaves. Simultaneously, water molecules (H2O) are absorbed from the soil by the plant's roots and transported to the leaves through specialised tissues.

In the chloroplasts, light energy is used to split water molecules into oxygen (O2) and hydrogen ions (H+). The released oxygen is released into the atmosphere as a by-product, enriching the air we breathe, while the hydrogen ions are used to fuel subsequent reactions.

Meanwhile, carbon dioxide molecules are combined with hydrogen ions and electrons from water to produce glucose (C6H12O6), a simple sugar molecule. This process, known as carbon fixation, forms the basis of organic carbon compounds essential for plant growth and development.

Photosynthesis is not only vital for plants but also sustains life on Earth by producing oxygen and serving as the primary source of energy for most ecosystems. Through the process of cellular respiration, organisms, including plants, animals, and microorganisms, release the stored energy in glucose to fuel their metabolic activities.

Moreover, photosynthesis plays a crucial role in regulating the Earth's climate by removing carbon dioxide from the atmosphere and mitigating the greenhouse effect. Plants act as carbon sinks, absorbing CO2 and storing it in their tissues, thereby helping to reduce the concentration of greenhouse gases in the atmosphere.

Understanding photosynthesis is essential for comprehending the interconnectedness of living organisms and the environment. It highlights the intricate balance of energy flow and nutrient cycling that sustains life on our planet.

Studying photosynthesis also has practical applications in agriculture, biotechnology, and environmental science. By manipulating photosynthetic processes, scientists can enhance crop productivity, develop renewable energy sources, and address pressing environmental challenges such as climate change and food security.

Cells

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Cells are the fundamental units of life, serving as the building blocks of all living organisms. These microscopic structures exhibit remarkable complexity and diversity, yet share common features and functions essential for survival.

At the core of every cell is the cell membrane, a thin, flexible barrier that encloses the cell and regulates the passage of molecules in and out. This semi-permeable membrane allows nutrients to enter the cell and waste products to exit, maintaining internal balance and integrity.

Within the cell, various organelles perform specialized functions to support life processes. The nucleus, often referred to as the cell's control centre, houses the cell's genetic material in the form of DNA. Here, the genetic instructions are stored and transcribed into RNA, which directs the synthesis of proteins essential for cell function and structure.

Other organelles, such as the mitochondria and chloroplasts, generate energy through cellular respiration and photosynthesis, respectively. These energy-producing organelles convert nutrients into adenosine triphosphate (ATP), the cell's primary energy currency, to fuel metabolic activities and sustain life processes.

Additionally, cells contain structures like the endoplasmic reticulum, Golgi apparatus, and lysosomes, which are involved in protein synthesis, processing, and transportation, as well as waste disposal and recycling.

The diversity of cell types and functions is vast, ranging from simple prokaryotic cells, such as bacteria, to complex eukaryotic cells found in plants, animals, and fungi. Each cell type exhibits unique adaptations and structures tailored to its specific role in the organism.

Understanding the structure and function of cells is essential for comprehending the complexity of living organisms and the processes that sustain life. It provides insights into the mechanisms of growth, development, and disease, as well as opportunities for biomedical research and technological innovation.

Moreover, studying cells contributes to various scientific disciplines, including biology, medicine, biotechnology, and environmental science. It enables advancements in areas such as regenerative medicine, drug discovery, and genetic engineering, with profound implications for human health and well-being.

Atoms

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Atoms are the fundamental building blocks of matter, forming the basis of everything in the universe, from the air we breathe to the stars in the sky. These minuscule particles exhibit extraordinary diversity and complexity, yet share common features and properties that govern their behaviour and interactions.

At the heart of every atom lies a nucleus, composed of positively charged protons and neutral neutrons, tightly packed together. Surrounding the nucleus are negatively charged electrons, which orbit the nucleus in distinct energy levels or shells. The number of protons determines the atom's identity and defines its chemical properties, giving rise to the various elements found in nature.

The periodic table of elements organises atoms based on their atomic number, which corresponds to the number of protons in the nucleus. This arrangement reveals patterns and trends in the properties of elements, such as their atomic mass, electronegativity, and reactivity.

Atoms can bond together to form molecules through chemical reactions, where electrons are shared, transferred, or attracted between atoms to achieve stable configurations. These bonds give rise to the countless compounds and substances that make up the world around us, from water and air to minerals and proteins.

Moreover, atoms are constantly in motion, vibrating and colliding with one another in a ceaseless dance of energy exchange. This dynamic behaviour underlies the principles of thermodynamics and kinetics, governing processes such as heat transfer, phase transitions, and chemical reactions.

Understanding atoms is essential for unlocking the mysteries of the physical world and advancing scientific knowledge and technology. It provides insights into the properties and behaviours of matter at the smallest scales, informing fields such as chemistry, physics, materials science, and nanotechnology.

Moreover, studying atoms has practical applications in various industries, including medicine, energy, and electronics. It enables the development of new materials, pharmaceuticals, and technologies, with profound implications for human health, sustainable development, and innovation.

Animal Biology (zoology)

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Prism / Refraction

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Test tubes

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Electricity circuits

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Energy: Potential and Kinetic

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Sources of Energy - Renewable and nonrenewable sources of energy

Potential and Kinetic Energy: - Potential energy - Kinetic energy - Potential and kinetic energy in systems - Law of conservation of energy

Heat Transfer: - Heating as a transfer of energy - Conduction - Convection - Radiation

Insulation and Energy Saving: - Using insulating materials

Energy Transfer to Surroundings: - Useful and ‘wasted’ energy

The National Electricity Supply System: - Energy transfers in the national grid - Conserving electricity in the home

The Biosphere: - The concept of the bioshpere - Requirements for sustaining life

Biodiversity: - Classification of living things - Diversity of animals - Diversity of plants

Sexual Reproduction: - Sexual Reproduction in Angiosperms - Human Reproduction

Variation: - Variations exists within a species

Properties of Materials: - Physical properties of materials - Impact on the environment

Seperating Mixtures: - Mixtures - Methods of physical seperation - Sorting and recycling materials

Acids, Bases and Neutrals: - Tastes of substances - Properties of acids, bases and neutrals - Acid-base indicators

Introduction to the Periodic Table of Elements: - Arrangement of elements on the Periodic Table - Some properties of metals, semi-metals and non-metals

Relationship of the Sun to the Earth: - Solar energy and the Earth's seasons - Solar energy and life on Earth - Stored solar energy

Relationship of the Moon to the Earth: - Relative positions - Gravity - Tides

Historical Development of Astronomy: - Early indigenous knowledge - Modern developments

Static Electricity: - Friction and static electricity

Energy Transfer in Electrical Systems: - Circuits and current electricity - Components of a circuit - Effects of an electric current

Series and Parallel Circuits: - Series circuits - Parallel circuits - Other output devices

Visible Light: - Radiation of light - Spectrum of visible light - Opaque and transparent substances - Absorption of light - Reflection of light - Seeing light - Refraction light

Photosynthesis and Respiration: - Photosynthesis - Respiration

Interactions and Interdependence Within the Environment: - Introduction to ecology - Ecosystems - Feeding relationships - Energy flow: Food chains and food webs - Balance in an ecosystem - Adaptations - Conservation of the ecosystem

Micro-organisms: - Types of micro-organisms - Harmful micro-organisms - Useful micro-organisms

Atoms: - Atoms - building blocks of matter - Sub atomic particles - Pure substances - Elements - Compounds - Mixtures of elements and compounds

Particle Model of Matter: - The concept of the particle model of matter - Change of state - Density, mass and volume - Density and states of matter - Density of different materials - Expansion and contraction of materials - Pressure

Chemical Reactions: - Reactants and products

The Solar System: - The Sun - Objects around the Sun - Earth's position in the Solar System

Beyond the Solar System: - The Milky Way Galaxy - Our nearest star - Light years, light hours and light minutes - Beyond the Milky Way Galaxy

Looking Into Space: - Early viewing of space - Telescopes

Forces: - Types of forces - Contact forces - Field forces (non-contact forces)

Electric Cells as Energy Systems: - Electric cells

Resistance: - Uses of resistors - Factors that affect resistance in a circuit - Field forces (non-contact forces)

Series and Parallel Circuits: - Series circuits - Parallel circuits

Safety with Electricity: - Safety practices

Energy and the National Electricity Grid: - Electricity generation - Nuclear power in South Africa - National electricity grid

Cost of Electrical Power: - The cost of power consumption

Cells as the Basic Units of Life: - Cell structure - Differences between plant and animal cells - Cells in tissues, organs and systems

Systems in the Human Body: - Body systems

Human Reproduction: - Purpose and puberty - Reproductive organs - Stages of reproduction

Circulatory and Respiratory Systems: - Breathing, gaseous exchange, circulation and respiration

Digestive System: - Healthy diet - The alimentary canal and digestion

Compounds: - The Periodic Table - Names of compounds

Chemical Reactions: - Chemical equations to represent reactions - Balanced equations

Reactions of Metals with Oxygen: - The general reaction of metals with oxygen - Reaction of iron with oxygen - Reaction of magnesium with oxygen - Formation of rust - Ways to prevent rusting

Reactions of Non-metals with Oxygen: - The general reaction of non-metals with oxygen - Reaction of carbon with oygen - Reaction of sulfur with oxygen

Acids and Bases, and pH Value: - The concept of pH value

Reactions of Acids with Bases: Part I: - Neutralisation and pH

Reactions of Acids with Bases: Part II: - The general reaction of an acid with a metal oxide (base) - Applications (base) - The general reaction of an acid with a metal hydroxide (base)

Reactions of Acids with Bases: Part III: - The general reaction of an acid with a metal carbonate (base)

Reactions of Acids with Metals: - Reactions of acids with metals

The Earth as a System: - Spheres of the Earth

Lithosphere: - Lithosphere - The rock cycle

Mining of Mineral Resources: - Extracting ores - Refining minerals - Mining in South Africa

Atmosphere: - Troposphere - Stratosphere - Mesosphere - Thermosphere - The greenhouse effect

Birth, Life and Death of Stars: - The birth of a star - Life of a star - Death of a star

Living and Non-living Things: - Living things - Non-living things

Structure of Plants and Animals: - Structure of plants - Structure of animals

What Plants Need to Grow: - Conditions for growth

Habitats of Animals: - Different habitats - Need for a habitat

Structures for Animal Shelters: - Animal shelters

Strengthening Materials: - Ways to strengthen materials

Strong Frame Structures: - Struts and frame structures - Indigenous structures

Materials Around Us: - Solids, liquids and gases - Change of state - The water cycle

Solid Materials: - Raw and manufactured materials - Properties of materials

Energy and Energy Transfer: - Energy for life - Energy from the Sun

Energy Around Us: - Energy - Input and output energy

Energy and Sound: - Vibrations and sound - Making sounds - Noise pollution

Movement and Energy in a System: - Movement and musical instruments

Rocket Systems: - Modelling a rocket

Planet Earth: - Features of the Earth - Earth and space

The Sun: - Our closest star

The Earth and the Sun: - Moving around the Sun - The Sun and life

The Moon: - Features of the Moon - Phases of the Moon - Moon stories

Plants and Animals on Earth: - Many different plants and animals - Inter-dependence - Animal types

Animal Skeletons: - Skeletons of vertebrates -Movement

Food Chains: - Food and feeding

Life Cycles: - Growth and development

Stored Energy in Fuels: - Fuels - Burning fuels -Safety with fire

Energy and Electricity: - Cells and batteries - Mains electricity - Safety with electricity

Energy and Movement: - Elastic and springs

Skeletons as Structures: - Frame and shell structures

Metals and Non-metals: - Properties of metals - Properties of non-metals

Uses of Metals: - Other properties of metals - Uses of metals

Processing Materials: - Combining materials

Processed Materials: - Properties and uses - Traditional processing

Systems for Moving Things: - Wheels and axles

Planet Earth: - The Earth moves

Surface of the Earth: - Rocks - Soil types

Sedimentary Rocks: - Formation of sedimentary rock - Uses of sedimentary rock

Fossils: - Fossils in rock - Body and trace fossils - Importance of South African fossils

Photosynthesis: - Plants and food - Plants and air

Nutrients in Food: - Food groups - Balanced diets

Ecosystems and Food Webs: - Different ecosystems - Living and non-living things in ecosystems - Food Webs

Solids, Liquids and Gases: - Arrangement of particles

Mixtures: - Mixtures of materials

Mixtures and Water Resources: - Water pollution - Importance of wetlands

Solutions as Special Mixtures: - Solutions - Soluble substances - Saturated solutions - Insoluble substances

Dissolving: - Rates of dissolving

Electric Circuits: - A simple circuit - Circuit diagrams

Electrical Conductors and Insulators: - Conductors - Insulators

Mains Electricity: - Fossil fuels and electricity - Cost of electricity - Illegal connections

Systems to Solve Problems: - Using electric circuits

Systems to Explore the Moon and Mars: - Vehicles used on the Moon - Vheicles used on Mars

Systems for Looking into Space: - Telescopes

The Solar System: - The Sun, planets and asteroids - Moons

Movement of the Earth and the Planets: - Rotation (Earth) - Revolution (Earth)

The Movement of the Moon: - Rotation (Moon) - Revolution (Moon)

Food Processing: - Need for processing food - Methods for processing food

Processes to Purify Water: - Clean water

Introduction to Vectors and Scalars: - Vectors - Scalars

Motion in One Direction: - Reference frame - Position - Displacement and distance - Average speed - Average velocity - Acceleration - Instantaneous velocity - Instantaneous speed

Energy: - Gravitational potential energy - Kinetic energy - Mechanical energy - Conservation of mechanical energy

Transverse Pulses on a String or Spring: - Pulse - Amplitude superposition of pulses

Transverse Waves: - Wavelength - Frequency - Amplitude - Period - Wave speed

Longitudinal Waves: - On a spring - Wavelength - Frequency - Amplitude - Period - Wave speed - Sound waves

Sound: - Pitch - Loudness - Quality (tone) - Ultrasound

Electromagnetic Radiation: - Dual (particle/wave) nature of electromagnetic (EM) radiation - Nature of EM radiation - EM spectrum

Magnetism: - Magnetic field of permanent magnets - Poles of permanent magnets - Attraction and repulsion - Magnetic field lines - Earth’s magnetic field - Compass

Electrostatics: - Two kinds of charge - Force exerted by charges on each other (descriptive) - Attraction between charged and uncharged objects (polarisation) - Charge conservation - Charge quantization

Electric Circuits: - EMF - Potential difference (pd) - Current - Measurement of voltage (pd) and current - Resistance - Resistors in parallel

Revise Matter and Classification: - Materials - Heterogeneous and homogeneous mixtures - Pure substances - Names and formulas - Metals and non-metals - Electrical and thermal conductors and insulators - Magnetic and nonmagnetic materials

States of Matter and the Kinetic Molecular Theory: - States of matter and the kinetic molecular theory

Atomic Structure: - Models of the atom - Atomic mass and diameter - Protons, Neutrons and electrons - Isotopes - Energy quantization and electron configuration

Periodic Table: - Position of the elements - Similarities in chemical properties in groups - Electron configuration in groups

Chemical Bonding: - Covalent bonding - Ionic bonding - Metallic bonding

Particles Substances are Made of: - Atoms and compounds - Molecular substances and ionic substances

Hydrosphere: - Hydrosphere

Physical and Chemical Change: - Separation by physical means - Separation by chemical means - Conservation of atoms and mass - Law of constant composition

Representing Chemical Change: - Balanced chemical equations

Reactions in Aqueous Solution: - Ions in aqueous solutions - Ion interaction - Electrolytes - Conductivity - Precipitation - Chemical reaction types

Stoichiometry: - Mole concept

Vectors in Two Dimensions: - Resultant of perpendicular vectors - Resolution of a vector into its parallel and perpendicular components

Newton’s Laws and Application of Newton’s Laws: - Newton’s first, second and third laws and Newton’s law of universal gravitation - Different kinds of forces - Force diagrams - Free body diagrams and application of Newton’s laws

Geometrical Optics: - Refraction - Snell’s Law - Critical angles and total internal reflection

2D and 3D Wave Fronts: - Diffraction

Electrostatics: - Coulomb’s Law - Electric field

Electromagnetism: - Magnetic field associated with current-carrying wires - Faraday’s Law

Electric Circuits: - Energy - Power

Molecular Structure: - A chemical bond - Molecular shape - Electronegativity and bond polarity - Bond energy and bond length

Intermolecular Forces: - Chemical bonds revised - Types of intermolecular forces - States of matter - Density - Kinetic energy - Temperature - Three phases of water (macroscopic properties related to sub-microscopic structure)

Ideal Gases: - Motion and kinetic theory of gases - Gas laws - Relationship between T and P

Lithosphere: - Mining - Energy resources

Stoichiometry: - Molar volume of gases - Concentration - Limiting reagents - Volume relationships in gaseous reactions

Energy and Chemical Change: - Energy changes related to bond energy - Exothermic and endothermic reactions - Activation energy

Types of Reactions: - Acid-base - Redox reactions - Oxidation numbers

Momentum and Impulse: - Momentum - Newton’s second law expressed in terms of momentum - Conservation of momentum and elastic and inelastic collisions - Impulse

Vertical Projectile Motion in One Dimension (1D): - Vertical projectile motion represented in words - Diagrams - Equations and Graphs

Work, Energy and Power: - Work - Work-energy theorem - Conservation of energy with non-conservative forces present - Power

Doppler Effect: - With sound and ultrasound - With light - red shifts in the universe

Electric Circuits: - Internal resistance and series-parallel networks

Electrodynamics: - Electrical machines (generators, motors) - Alternating current

Optical Phenomena and Properties of Materials: - Photo-electric effect - Emission and absorption spectra

Organic Chemistry: - Functional groups - Saturated and unsaturated structures - Isomers - Naming and formulae - Physical properties - Chemical reactions (substitution, addition and elimination)

Organic Macromolecules: - Plastics and polymers

Chemical Industry: - Fertilizer industry

Reaction Rate: - Factors affecting rate - Measuring rate - Mechanism of reaction and of catalysis

Chemical Equilibrium: - Factors affecting equilibrium - Equilibrium constant - Application of equilibrium principles

Acids and Bases: - Reactions - Titrations - pH - Salt hydrolysis

Electrochemical reactions: - Electrolytic and galvanic cells - Relation of current and potential to rate and equilibrium - Standard electrode potentials - Oxidation and reduction half reaction and cell reactions - Oxidation numbers - Application of redox reactions

Renewable and non-renewable sources of energy

Curriculum

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Renewable and non-renewable sources of energy

• energy is needed to make everything work, move or live
• a source of energy has energy stored waiting to be used, or energy that is needed to make something happen
• non-renewable sources of energy cannot be replenished once used, such as fossil fuels (coal, oil, natural gas) and nuclear fuels (such as uranium)

          [Links to Planet Earth and Beyond Grade 7 term 4]

• renewable sources of energy are continually replenished, such as hydro power, wind, sunlight, biofuel (wood).

Suggested Activities

• Listing non-renewable energy sources. Explain why they are regarded as non-renewable.
• Listing renewable energy sources. Explain why they are regarded as renewable.

Biodiversity

Curriculum

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Classification of living things

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• plants, animals and microorganisms, and their habitats make up the total biodiversity of the Earth
• living organisms are sorted and classified according to their shared characteristics
• scientists have grouped the organisms into a classification system
• the five main groups (called Kingdoms) of living organisms include Bacteria, Protista, Fungi, Plants and Animals
• basic differences in processes such as movement, nutrition and reproduction, distinguishes plants from animals
• Kingdoms are further subdivided into Phyla/Divisions, then Classes, then Families, then Orders, then Genera, and the smallest group is Species

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Suggested Activities

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• Grouping a selection of everyday objects according to observable features, for example shape, colour, size, and use
• drawing up a table of the basic differences between plants and animals
• sorting vertebrates and invertebrates using observable characteristics

Introduction to the Periodic Table of Elements

Curriculum

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Arrangement of elements on the Periodic Table

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• the Periodic Table of Elements is a classification system for the elements which make up matter and materials in the world [an element is a pure substance which cannot be broken down further]
• the Periodic Table was devised by Dmitri Mendeleev in the 1860s. He arranged the elements according to their properties in a table format
• the elements of the Periodic Table are arranged into three main categories:
  metals, semi-metals and non-metals:
• metals are arranged on the left hand side of the table
• non-metals are found on the far right hand side of the table
• semi-metals are found in the region between metals and non-metals
• each element has its own name, symbol, atomic number and position on the Periodic Table.

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Some properties of metals, semi-metals and non-metals

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• metals are usually shiny, ductile and malleable, solid (except mercury) and have high melting and boiling points
• non-metals have a variety of different properties (depending on whether they are solids or gases)
• semi-metals are solids and have some properties of metals and some properties of non-metals

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Suggested Activities

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• reading about and learning the names of the first 20 elements of the Periodic Table [learners need NOT memorise the atomic number of each element]
• categorising the elements in a copy of the Periodic Table by colouring each category (metals, semi-metals and non-metals) in different colours
• identifying a number of elements from the Periodic Table used in everyday life/ the household. Describe them in writing.

Atoms

Curriculum

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Atoms - building blocks of matter

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• all matter is made up of tiny particles called atoms
• an element is made up of atoms of the same kind. For example, all the atoms of an element, such as copper, are identical
• an element is a substance that cannot be broken down into two or more substances by chemical means (An element cannot be changed into another element by means of a chemical reaction)
• atoms of one element differ from the atoms of all other elements
• all known elements are listed on the Periodic Table of the Elements

Sub atomic particles

• atoms are made up of smaller sub-atomic particles (protons, neutrons and electrons)
• the central region of the atom is called the nucleus
• the nucleus is made up of positively charged particles called protons and neutral particles called neutrons
• negatively charged particles called electrons move around the nucleus
• atoms are neutral because the number of negatively charged particles (electrons) is equal to the number of positively charged particles (protons)

Pure substances

• elements and compounds are pure substances

Elements

• an element is a material that consists of atoms of only one kind, such as hydrogen (H), oxygen (O), carbon (C), sodium (Na) and chlorine (Cl)
• all known elements are listed on the Periodic Table of Elements. They are limited in number and are the building blocks of millions of compounds
• some elements on the Periodic Table of Elements form diatomic molecules, for example, hydrogen (H2), nitrogen (N2), oxygen (O2), chlorine (Cl2). These are called molecules of elements
• sometimes atoms react together chemically to form molecules of compounds (such as H2O, CO2)

Compounds

• a compound is a material that consists of atoms of two or more different elements chemically bonded together, such as water (H2O), carbon dioxide (CO2), salt (NaCl)
• the atoms in a given compound are always combined/bonded in a fixed ratio such as in water, where the ratio is always two hydrogen atoms (H) to one oxygen atom (O)
• a chemical bond is the force that holds atoms together
• compounds [such as water (H2O), carbon dioxide (CO2), salt (NaCl) are formed by chemical reactions
• compounds can be broken down in a decomposition reaction into other compounds or their original elements by heating or electrolysis. For example, electrolysis decomposes water (H2O) to form hydrogen (H2) and oxygen (O2)

Mixtures of elements and compounds

• elements and compounds are often found mixed together, such as in air, sea water, rocks, and in living things
• mixtures are separated by physical means; compounds can be separated by chemical means.

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Suggested Activities

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• making a 2-dimensional model or drawing of an atom (choose an element from the first 20 elements from the Periodic Table) [Use beads or dried lentils or dried peas pasted with glue onto a paper plate, to make a basic model of an atom of a selected element. Show protons and neutrons making up the nucleus, and electrons in the space around the nucleus]
• making models showing the atoms which make up molecules (such as O2, H2, N2 , H2O, CO2), using plastic “popit” beads or modelling clay or playdough
• demonstrating and recording observations of how a compound can be broken down into elements by electrolysis - copper(II) chloride (CuCl2) solution decomposes to form copper (Cu) and chlorine (Cl2) [use carbon electrodes and a power source of about 3 to 9 volts]
  and/or
• demonstrating and recording observations of how a compound decomposes into elements by heating - potassium permanganate (KMnO4) to obtain oxygen (O2)
[Note: oxygen is not the only product]. Test for O2

[Note: a glowing splint is used to test for the presence of oxygen gas. It re-lights in oxygen gas]

The Solar System

Curriculum

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The Solar System

The Sun

• the Sun is like all other stars – it produces large amounts of heat and light continuously
• the energy in our Sun comes from powerful nuclear reactions during which hydrogen gas changes into helium gas

Objects around the Sun

• a variety of objects orbit the Sun – eight planets and their moons, rocky asteroids, outer dwarf planets and many distant icy and dusty objects in the Kuiper Belt and Oort Cloud, at the edge of the Solar System
• all the planets and other objects in the Solar System have their own special features including size, distance from the Sun, number of moons known, composition, surface temperature, time it takes for one orbit around the Sun
• comets from the Oort Cloud come close to the Sun from time to time
• the Solar System looks like a flat disc or plate. The Sun spins (rotates) at the centre and the planets and all other objects orbit around it in the same direction
• gravity is the force that keeps all these objects in their stable, predictable orbits around the Sun

Earth’s position in the Solar System

• the Earth is the third planet from the Sun
• the Earth is the only planet that is known to support life
• the conditions that support life on Earth include:
• temperature: Earth’s distance from the Sun provides the ideal temperature range
• water is a liquid, gas or solid in Earth’s temperature range
• sunlight provides the energy in the food chain
• oxygen: early life forms and algae produced enough oxygen for the evolution of more sophisticated life forms

Suggested activities

• constructing a model of the Solar System showing relative distances of the planets from the Earth and relative sizes of planets
• interpreting a table of facts about the Solar System
• comparing and writing about the conditions on other planets in our Solar System including their special features

OR

• presenting a fact sheet about any object found in our Solar System
• writing about why the conditions on Earth are ideal for life

Energy and the national electricity grid

Curriculum

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Energy and the national electric grid

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• A power station is a system for generating electricity.
• most power stations in South Africa use coal as a fuel to boil water
• the steam from the water turns a turbine which turns a generator, which produces electricity
• there are other alternative sources of energy besides coal that can be used to drive turbines and generators including wind, falling water (hydroelectric), sun-heated steam, nuclear fission, waves in the sea.

Nuclear power in South Africa

• a nuclear power station such as Koeberg in the Cape, uses radioactive fuel, the radioactivity produces heat by nuclear fission. The heat is then used to boil water to produce steam
• the steam from the water turns a turbine which turns a generator, that produces electricity. The electricity is then channelled into the national electricity grid
• spent nuclear fuel (nuclear waste) is still radioactive and remains so for many hundreds of years, therefore it needs to be properly disposed of so it is not a danger to life for years to come
• the national grid is a network of interacting parts (a system): change in one part of the grid affects other parts of the grid
• power stations feed electrical energy into the national grid at high voltages
• power lines carry electricity at high voltages
• transformers step down the voltage for local distributors and consumers: 15% of energy is wasted due to heating of transmission lines and transformers [No details are required of alternating current or step-down transformers]
• power surges and grid overload can disrupt the power supply

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Suggested Activities

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researching about alternative sources of energy that can be used to drive generators for the national grid. Compare them in terms of sustainability and environmental impact

Compounds

Curriculum

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Briefly review and revise concepts dealt with in Grade 8, focusing on compounds

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The Periodic Table

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[Note: use the Periodic Table of Elements as a reference tool in the topics that follow]

• the elements can be classified into metals, non-metals and semi metals
• the elements found in groups (vertical columns) have similar chemical properties
• each element on the Periodic Table (in its own block) has an atomic number (smaller number), mass number (larger number), name and symbol
• a formula/e is ratio of the symbols of the elements and number of atoms for each symbol in a compound

Names of compounds

• many compounds are named according to their elements, such as sodium chloride (table salt) which is made of the elements sodium and chlorine. But others have common names such as water and ammonia
• some compounds have names such as carbon monoxide CO, carbon dioxide CO2, sulfur trioxide SO3. In these compounds:
  
  • monoxide- tells us that one oxygen atom has combined with the carbon atom
  • dioxide- tells us that two oxygen atoms have combined with the carbon atom
  • trioxide- tells us that three oxygen atoms have combined with the sulfur atom

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Suggested Activities

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• memorising the name and the symbol of each of the first 20 elements, on the Periodic Table, as well as iron (Fe), copper (Cu), zinc (Zn) [learners need not memorise the atomic number of each element]
• naming, writing symbols, and drawing pictures

or

• making models (using beads, beans or plasticine or playdough) of several elements and compounds. Including: water (H2O), oxygen (O2), carbon monoxide (CO), carbon dioxide (CO2), copper oxide (CuO), sodium chloride (NaCl), sulfur trioxide (SO3)

[Note: the latest internationally accepted spelling is now sulfur not sulphur]

Grade 9: Systems in the human body

Curriculum

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[Note: The intention of this topic is to provide learners with an overview of the structure and functions of organs and systems in the human body]

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Body systems

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• the human body consists of several integrated systems working together including the following:
• digestive system: breaks down food into dissolved nutrients that can be absorbed into the blood stream and transported to cells throughout the body
• the main processes include ingestion, digestion, absorption and egestion
• the main components include the mouth, oesophagus, stomach, intestines, liver
• health issues include ulcers, anorexia nervosa, diarrhoea, liver cirrhosis
• circulatory system: brings nutrients and oxygen to cells and removes waste products
• the main processes include circulating blood between heart and lungs, and circulating blood between the heart and the rest of the body
• the main components include the heart, blood vessels (arteries, veins, capillaries), blood
• health issues include high blood pressure, heart attacks, strokes
• respiratory system: is responsible for supplying oxygen to the body and for removing carbon dioxide
• the main processes include breathing (inhalation and exhalation), gaseous exchange (diffusion) and respiration
• the main components include the nose and mouth, trachea and other air passageways, lungs, blood
• health issues include asthma, lung cancer, bronchitis, asbestosis
• musculoskeletal system: muscles produce body movement. The skeleton protects the body, provides support and enables movement
• the main processes include contraction and relaxation of muscles, locomotion and movement
• the main components include the muscles, bones, cartilage, tendons, ligaments 
• health issues include rickets, arthritis, osteoporosis
• excretory system: removes waste from the blood and regulates the body’s fluids
• the main processes include filtration, absorption, diffusion, excretion
• the main components include the kidneys, bladder, ureters
• health issues include kidney failure, bladder infection, kidney stones
• nervous system: receives and helps the body respond to stimuli
• the main processes include hearing, seeing, feeling, tasting, smelling, sending and receiving impulses, regulating temperature
• the main components include the brain, spinal cord, nerves, ears, nose, eyes, skin, tongue
• health issues include deafness, blindness, short sightedness, effects of drugs and alcohol on the brain
• reproductive system: produces sex cells for the purpose of continuation of the species
• the main processes include growth, cell division, maturation, copulation, ejaculation, ovulation, menstruation, fertilisation, implantation
• the main components include testes, ovaries, uterus
• health issues include infertility, foetal alcohol syndrome, STDs

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Suggested Activities

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• drawing a large outline of the human body. Draw and label each system [as it is dealt with], onto the outline [photocopy one outline of the human body for each learner, as well as a set of systems and organs which they can cut out and stick onto the outline]
• researching and writing about the health issues related to each system
  • producing a poster advocating healthy life style choices

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