1. PROCESSING FOOD.
TERMINOLOGY:
1. Process – This is when something is changed into a different form.
2. Preserve – This is when food is processed so that it stays in its original state.
3. Micro-organisms – These are tiny living creatures that are too small for us to see without a microscope.
4. Indigenous people – are the original or first people to live in a country.
5. Mould – these are different types of fungus that grow on food.
6. Yeasts – These are tiny living creatures that attack fresh foods that contain sugar.
7. Evaporates – This is when water changes to water vapour.
8. Hygienic – This means that you keep the food clean and safe for people to eat.
Why do we process food:
Ø To change their flavour (What they taste like) or texture (what they feel like in your mouth) or appearance (what they look like)
Ø To preserve them (make them last longer)
ü People need fresh food such as fruit, vegetables, meat, fish and eggs in order to stay healthy.
ü Most fresh food rots quickly.
ü Rotten food smells and tastes bad and can be poisonous.
ü Bacteria, mould and yeast are micro-organisms that make food rot.
ü Some moulds are useful and can be used to cure illnesses e.g. The first antibiotic called Penicillin was made from mould.
ü Yeast is used to make bread, wine and beer.
Ways of preserving food:
ü Ancient people all over the world found ways to make food last longer.
ü There were times when they would have plenty of food from hunting, gathering wild plants or harvesting crops, etc.
ü These people preserved the food for times when they could not find or grow enough food.
Different ways of preserving food:
o Making cheese from milk.
o Drying meat, fish, grains and fruit.
o Salting meat and fish.
o Hanging meat over fires to preserve with smoke.
o Making wine, beer, and other alcoholic drinks from fruit, vegetables and grains.
Saturday, September 11, 2010
FORMATION OF IGNEOUS ROCKS
IGNEOUS ROCKS
Igneous rocks are called fire rocks and are formed either underground or above ground. Underground, they are formed when the melted rock, called magma, deep within the earth becomes trapped in small pockets. As these pockets of magma cool slowly underground, the magma becomes igneous rocks.
Igneous rocks are also formed when volcanoes erupt, causing the magma to rise above the earth's surface. When magma appears above the earth, it is called lava. Igneous rocks are formed as the lava cools above ground.
Granite rocks are igneous rocks which were formed by slowly cooling pockets of magma that were trapped beneath the earth's surface. Granite is used for long lasting monuments and for trim and decoration on buildings.
Scoria rocks are igneous rocks which were formed when lava cooled quickly above ground. You can see where little pockets of air had been. Scoria is actually a kind of glass and not a mixture of minerals.
Pumice rocks are igneous rocks which were formed when lava cooled quickly above ground. You can see where little pockets of air had been. This rock is so light, that many pumice rocks will actually float in water. Pumice is actually a kind of glass and not a mixture of minerals. Because this rock is so light, it is used quite often as a decorative landscape stone. Ground to a powder, it is used as an abrasive in polish compounds and in Lava© soap.
Obsidian rocks are igneous rocks that form when lava cools quickly above ground. Obsidian is actually glass and not a mixture of minerals. The edges of this rock are very sharp.
Igneous rocks are called fire rocks and are formed either underground or above ground. Underground, they are formed when the melted rock, called magma, deep within the earth becomes trapped in small pockets. As these pockets of magma cool slowly underground, the magma becomes igneous rocks.
Igneous rocks are also formed when volcanoes erupt, causing the magma to rise above the earth's surface. When magma appears above the earth, it is called lava. Igneous rocks are formed as the lava cools above ground.
Granite rocks are igneous rocks which were formed by slowly cooling pockets of magma that were trapped beneath the earth's surface. Granite is used for long lasting monuments and for trim and decoration on buildings.
Scoria rocks are igneous rocks which were formed when lava cooled quickly above ground. You can see where little pockets of air had been. Scoria is actually a kind of glass and not a mixture of minerals.
Pumice rocks are igneous rocks which were formed when lava cooled quickly above ground. You can see where little pockets of air had been. This rock is so light, that many pumice rocks will actually float in water. Pumice is actually a kind of glass and not a mixture of minerals. Because this rock is so light, it is used quite often as a decorative landscape stone. Ground to a powder, it is used as an abrasive in polish compounds and in Lava© soap.
Obsidian rocks are igneous rocks that form when lava cools quickly above ground. Obsidian is actually glass and not a mixture of minerals. The edges of this rock are very sharp.
PHYLUM COELENTERATA
COELENTERATA
Coelenterata is an obsolete long term encompassing two animal phyla, the Ctenophore (comb jellies) and the Cnidaria (coral animals, true jellies, sea anemones, sea pens, and their allies). The name comes from the Greek "koilos" ("full bellied"), referring to the hollow body cavity common to these two phyla. They have very simple tissue organization, with only two layers of cells, external and internal.
The term coelenterate is no longer recognized as scientifically valid, as the Cnidaria and Ctenophora have placed at equal rank under the Metazoa with the other phyla of animals. Cnidaria means "to sting" A single term encompassing these two phyla but leaving out all others of equal rank would be considered polyphyletic. Nonetheless, the term coelenterate is still used in informal settings to refer to the Cnidaria and Ctenophora.
Complicating the issue is the 1997 work of Lynn Margulis (revising an earlier model by Thomas Cavalier-Smith) that placed the Cnidaria and Ctenophora alone under the Radiata branch of the Eumetazoa subregnum. (The latter refers to all the animals except the sponges, Trichoplax, and the still poorly-understood Mesozoa.) Neither grouping is accepted universally; however, both are commonly encountered in taxonomic literature.
The term coelenterate is no longer recognized as scientifically valid, as the Cnidaria and Ctenophora have placed at equal rank under the Metazoa with the other phyla of animals. Cnidaria means "to sting" A single term encompassing these two phyla but leaving out all others of equal rank would be considered polyphyletic. Nonetheless, the term coelenterate is still used in informal settings to refer to the Cnidaria and Ctenophora.
Complicating the issue is the 1997 work of Lynn Margulis (revising an earlier model by Thomas Cavalier-Smith) that placed the Cnidaria and Ctenophora alone under the Radiata branch of the Eumetazoa subregnum. (The latter refers to all the animals except the sponges, Trichoplax, and the still poorly-understood Mesozoa.) Neither grouping is accepted universally; however, both are commonly encountered in taxonomic literature.
PHYLUM PROTOZOA
PROTOZOA
Protozoa (from the Greek words proton, meaning "first", and zoa, meaning "animals") is a subkingdom of microorganisms that are classified generally as unicellular non-fungal eukaryotes. Protozoans are a major component of the ecosystem.
The word protozoan is originally an adjective and is used as a noun While there is not any exact definition for the term protozoan, most scientists use the word to refer to a unicellular heterotrophic protist, such as the amoeba and ciliate. The term algae is used for microorganisms that photosynthesize. However, the distinction between protozoa and algae is often vague. For example, the algae Dinobryon has chloroplasts for photosynthesis, but it can also feed on organic matter and is motile. Protozoans are referred to generally as animal-like protists.
The Protozoa are a paraphyletic group (it does not include all genetic relatives of the group). They constitute their own "kingdom" by the Integrated Taxonomic Information System 2009 classification.
The word protozoan is originally an adjective and is used as a noun While there is not any exact definition for the term protozoan, most scientists use the word to refer to a unicellular heterotrophic protist, such as the amoeba and ciliate. The term algae is used for microorganisms that photosynthesize. However, the distinction between protozoa and algae is often vague. For example, the algae Dinobryon has chloroplasts for photosynthesis, but it can also feed on organic matter and is motile. Protozoans are referred to generally as animal-like protists.
The Protozoa are a paraphyletic group (it does not include all genetic relatives of the group). They constitute their own "kingdom" by the Integrated Taxonomic Information System 2009 classification.
HERBIVORES
HERBIVORES
Herbivores are animals that are adapted to eat plants. Herbivory is a form of predation in which an organism consumes principally autotrophs] such as plants, algae and photosynthesizing bacteria. More generally, organisms that feed on autotrophs in general are known as primary consumers.
By strict interpretation of this definition, many fungi, some bacteria, many animals, some protists and a small number of parasitic plants might be considered herbivores. However, herbivory generally refers to animals eating plants. Fungi, bacteria and protists that feed on living plants are usually termed plant pathogens (plant diseases). Microbes that feed on dead plants are saprotrophs. Flowering plants that obtain nutrition from other living plants are usually termed parasitic plants.
By strict interpretation of this definition, many fungi, some bacteria, many animals, some protists and a small number of parasitic plants might be considered herbivores. However, herbivory generally refers to animals eating plants. Fungi, bacteria and protists that feed on living plants are usually termed plant pathogens (plant diseases). Microbes that feed on dead plants are saprotrophs. Flowering plants that obtain nutrition from other living plants are usually termed parasitic plants.
CARNIVORES
CARNIVORES
A carnivore (pronounced, meaning 'meat eater' (Latin carne meaning 'flesh' and vorare meaning 'to devour'), is an organism that derives its energy and nutrient requirements from a diet consisting mainly or exclusively of animal tissue, whether through predation or scavenging. Animals that depend solely on animal flesh for their nutrient requirements are considered obligate carnivores while those that also consume non-animal food are considered facultative carnivores. Omnivores also consume both animal and non-animal food, and apart from the more general definition, there is no clearly defined ratio of plant to animal material that would distinguish a facultative carnivore from an omnivore, or an omnivore from a facultative herbivore, for that matter. A carnivore that sits at the top of the food chain is an apex predator.
Plants that capture and digest insects are called carnivorous plants. Similarly, fungi that capture microscopic animals are often called carnivorous fungi.
Plants that capture and digest insects are called carnivorous plants. Similarly, fungi that capture microscopic animals are often called carnivorous fungi.
AMPHIBIANS
PHYLUM AMPHIBIA
Amphibians (class Amphibia, from Amphi- meaning "on both sides" and -bios meaning "life"), such as frogs, toads, salamanders, newts, and caecilians, are exothermic (or cold-blooded) animals that metamorphose from a juvenile water-breathing form, either to an adult air-breathing form, or to a pseudomorph that retains some juvenile characteristics. Proteidae (mudpuppies and waterdogs) are good examples of pseudomorphic species. Though amphibians typically have four limbs, the caecilians are notable for being limbless. Unlike other land vertebrates (amniotes), most amphibians lay eggs in water. Amphibians are superficially similar to reptiles.
Amphibians are ecological indicators, and in recent decades there has been a dramatic decline in amphibian populations around the globe. Many species are now threatened or extinct.
Amphibians evolved in the Devonian Period and were top predators in the Carboniferous and Permian Periods, but many lineages were wiped out during the Permian–Triassic extinction. One group, the metoposaurs, remained important predators during the Triassic, but as the world became drier during the Early Jurassic they died out, leaving a handful of relict temnospondyls like Koolasuchus and the modern orders of Lissamphibia.
Amphibians are ecological indicators, and in recent decades there has been a dramatic decline in amphibian populations around the globe. Many species are now threatened or extinct.
Amphibians evolved in the Devonian Period and were top predators in the Carboniferous and Permian Periods, but many lineages were wiped out during the Permian–Triassic extinction. One group, the metoposaurs, remained important predators during the Triassic, but as the world became drier during the Early Jurassic they died out, leaving a handful of relict temnospondyls like Koolasuchus and the modern orders of Lissamphibia.
Omnivores
Omnivore
Omnivores are species that eat both plants and animals as their primary food source. They are opportunistic, general feeders not specifically adapted to eat and digest either meat or plant material primarily. Pigs are one well-known example of an omnivore. Crows are another example of an omnivore that many people see every day. Humans are regarded as omnivores. Although the term omnivore literally means eater of everything, omnivores cannot really eat "everything" that other animals eat; they can only eat things that are at least moderately easy to get and still at least moderately nutritious. For example, most of them cannot live by grazing (easy to get, but not nutritious enough), nor can they eat some hard-shelled animals or successfully hunt large or fast prey (nutritious, but too hard to get).
Although there are cases of herbivores eating meat matter, as well as examples of carnivores eating plants, the classification refers to the adaptations and main food source of the species in general, so these exceptions do not make either individual animals nor the species as a whole omnivores.
Most bear species are considered omnivores, but individual diets can range from almost exclusively herbivorous to almost exclusively carnivorous, depending on what food sources are available locally and seasonally. Polar bears are classified as carnivores while pandas are classified as herbivores, although giant pandas will eat some meat (e.g., insects) from time to time, and polar bears will sometimes eat plants (e.g., kelp) but neither is a significant part of their diet.
Although there are cases of herbivores eating meat matter, as well as examples of carnivores eating plants, the classification refers to the adaptations and main food source of the species in general, so these exceptions do not make either individual animals nor the species as a whole omnivores.
Most bear species are considered omnivores, but individual diets can range from almost exclusively herbivorous to almost exclusively carnivorous, depending on what food sources are available locally and seasonally. Polar bears are classified as carnivores while pandas are classified as herbivores, although giant pandas will eat some meat (e.g., insects) from time to time, and polar bears will sometimes eat plants (e.g., kelp) but neither is a significant part of their diet.
SYMBIOSIS
SYMBIOSIS
Symbiosis is close and often long-term interactions between different biological species. In 1877 Bennett used the word symbiosis (which previously had been used of people living together in community) to describe the mutualistic relationship in lichens[1] . In 1879 by the German mycologist Heinrich Anton de Bary, defined it as "the living together of unlike organisms." The definition of symbiosis is in flux, and the term has been applied to a wide range of biological interactions. The symbiotic relationship may be categorized as mutualistic, commensal, or parasitic in nature. Some symbiotic relationships are obligate, meaning that both symbionts entirely depend on each other for survival. For example, many lichens consist of fungal and photosyntheitc symbionts that cannot live on their own. Others are facultative, meaning that they can but do not have to live with the other organism.
Symbiotic relationships include those associations in which one organism lives on another (ectosymbiosis, such as mistletoe), or where one partner lives inside the other (endosymbiosis, such as lactobacilli and other bacteria in humans or zooxanthelles in corals). Symbiotic relationships may be either obligate, i.e., necessary for the survival of at least one of the organisms involved, or facultative, where the relationship is beneficial but not essential for survival of the organisms.
Symbiotic relationships include those associations in which one organism lives on another (ectosymbiosis, such as mistletoe), or where one partner lives inside the other (endosymbiosis, such as lactobacilli and other bacteria in humans or zooxanthelles in corals). Symbiotic relationships may be either obligate, i.e., necessary for the survival of at least one of the organisms involved, or facultative, where the relationship is beneficial but not essential for survival of the organisms.
VOLCANIC ERUPTION
VOLCANIC ERUPTION:
A volcano is an opening, or rupture, in a planet's surface or crust, which allows hot magma, ash and gases to escape from below the surface.
Volcanoes are generally found where tectonic plates are diverging or converging. A mid-oceanic ridge, for example the Mid-Atlantic Ridge, has examples of volcanoes caused by divergent tectonic plates pulling apart; the Pacific Ring of Fire has examples of volcanoes caused by convergent tectonic plates coming together. By contrast, volcanoes are usually not created where two tectonic plates slide past one another. Volcanoes can also form where there is stretching and thinning of the Earth's crust (called "non-hotspot intra-plate volcanism"), such as in the East African Rift, the Wells Gray-Clearwater volcanic field and the Rio Grande Rift in North America.
Volcanoes can be caused by mantle plumes. These so-called hotspots, for example at Hawaii, can occur far from plate boundaries. Hotspot volcanoes are also found elsewhere in the solar system, especially on rocky planets and moons
A volcano is an opening, or rupture, in a planet's surface or crust, which allows hot magma, ash and gases to escape from below the surface.
Volcanoes are generally found where tectonic plates are diverging or converging. A mid-oceanic ridge, for example the Mid-Atlantic Ridge, has examples of volcanoes caused by divergent tectonic plates pulling apart; the Pacific Ring of Fire has examples of volcanoes caused by convergent tectonic plates coming together. By contrast, volcanoes are usually not created where two tectonic plates slide past one another. Volcanoes can also form where there is stretching and thinning of the Earth's crust (called "non-hotspot intra-plate volcanism"), such as in the East African Rift, the Wells Gray-Clearwater volcanic field and the Rio Grande Rift in North America.
Volcanoes can be caused by mantle plumes. These so-called hotspots, for example at Hawaii, can occur far from plate boundaries. Hotspot volcanoes are also found elsewhere in the solar system, especially on rocky planets and moons
THE FORMATION OF SEDIMENTARY ROCKS
SEDIMENTARY ROCKS
For thousands, even millions of years, little pieces of our earth have been eroded--broken down and worn awayby wind and water. These little bits of our earth are washed downstream where they settle to the bottom of the rivers, lakes, and oceans. Layer after layer of eroded earth is deposited on top of each. These layers are pressed down more and more through time, until the bottom layers slowly turn into rock.
Sandstone rocks are sedimentary rocks made from small grains of the minerals quartz and feldspar. They often form in layers as seen in this picture. They are often used as building stones.
Limestone rocks are sedimentary rocks that are made from the mineral calcite which came from the beds of evaporated seas and lakes and from sea animal shells. This rock is used in concrete and is an excellent building stone for humid regions.
Shale rock is a type of sedimentary rock formed from clay that is compacted together by pressure. They are used to make bricks and other material that is fired in a kiln.
Conglomerate rocks are sedimentary rocks. They are made up of large sediments like sand and pebbles. The sediment is so large that pressure alone cannot hold the rock together; it is also cemented together with dissolved minerals.
Gypsum rocks are sedimentary rocks made up of sulfate mineral and formed as the result of evaporating sea water in massive prehistoric basins. It is very soft and is used to make Plaster of Paris, casts, molds, and wallboards.
For thousands, even millions of years, little pieces of our earth have been eroded--broken down and worn awayby wind and water. These little bits of our earth are washed downstream where they settle to the bottom of the rivers, lakes, and oceans. Layer after layer of eroded earth is deposited on top of each. These layers are pressed down more and more through time, until the bottom layers slowly turn into rock.
Sandstone rocks are sedimentary rocks made from small grains of the minerals quartz and feldspar. They often form in layers as seen in this picture. They are often used as building stones.
Limestone rocks are sedimentary rocks that are made from the mineral calcite which came from the beds of evaporated seas and lakes and from sea animal shells. This rock is used in concrete and is an excellent building stone for humid regions.
Shale rock is a type of sedimentary rock formed from clay that is compacted together by pressure. They are used to make bricks and other material that is fired in a kiln.
Conglomerate rocks are sedimentary rocks. They are made up of large sediments like sand and pebbles. The sediment is so large that pressure alone cannot hold the rock together; it is also cemented together with dissolved minerals.
Gypsum rocks are sedimentary rocks made up of sulfate mineral and formed as the result of evaporating sea water in massive prehistoric basins. It is very soft and is used to make Plaster of Paris, casts, molds, and wallboards.
THE STAGES OF HUMAN EVOLUTION
THE STAGES OF HUMAN EVOLUTION
The evolution of human started from an ape, When this apes started to stand upright it made this hominids ‘ hands free to make and use tools. Then came the more developed hominid, known as Homo habilis (meaning “handy human”). This hominid had a larger brain and used basic tools like handy axes. They ate mainly vegetables, but used tools to cut their food.
Homo erectus (meaning “upright human”) was a more advanced hominid with a bigger brain than Homo habilis. They developed different tools to do specific jobs. They lived in Africa for more than a million years before they started to move to the other parts of the world. They did this because they could walk upright and their bigger brains made it possible for them to adapt to any environment. They were the first to use fire. This is evident by the burnt areas of clay at sites in Kenya. Some pieces of burnt bones in the Swartkrans caves in South Africa suggested that hominids were eating cooked food.
People who looked like modern humans developed about 120 000 years ago. They are called Homo sapiens (meaning “wise human”). They lived in cave and made shelters using wood and animal skins. They used fire, and were very good tool makers and hunters. They were able to talk to each other, and so language started to develop. They had a regular supply of meat, which they could digest easily because it was cooked. Because of this they became physically and mentally stronger.
Finally fully developed modern humans developed. They are called Homo sapiens sapiens. They created smaller tools and made wooden handles for some of their tools. They used stone-tipped spears which improved their hunting and made their diet to become better. Those who lived in the coastal areas ate fish, seals, dolphins, seabirds and shellfish. There is evidence that they used red ochre powder for painting. This shows that they were developing new way to express themselves.
Homo erectus (meaning “upright human”) was a more advanced hominid with a bigger brain than Homo habilis. They developed different tools to do specific jobs. They lived in Africa for more than a million years before they started to move to the other parts of the world. They did this because they could walk upright and their bigger brains made it possible for them to adapt to any environment. They were the first to use fire. This is evident by the burnt areas of clay at sites in Kenya. Some pieces of burnt bones in the Swartkrans caves in South Africa suggested that hominids were eating cooked food.
People who looked like modern humans developed about 120 000 years ago. They are called Homo sapiens (meaning “wise human”). They lived in cave and made shelters using wood and animal skins. They used fire, and were very good tool makers and hunters. They were able to talk to each other, and so language started to develop. They had a regular supply of meat, which they could digest easily because it was cooked. Because of this they became physically and mentally stronger.
Finally fully developed modern humans developed. They are called Homo sapiens sapiens. They created smaller tools and made wooden handles for some of their tools. They used stone-tipped spears which improved their hunting and made their diet to become better. Those who lived in the coastal areas ate fish, seals, dolphins, seabirds and shellfish. There is evidence that they used red ochre powder for painting. This shows that they were developing new way to express themselves.
HUMAN EVOLUTION
HUMAN EVOLUTION
Some people think that the history of South Africa does not go back very far, but they are wrong. We have the oldest history in the world. Proof of the first “human-like” creatures is found in Southern and East Africa. There is evidence that suggest human life began in Southern Africa and then spread to the rest of the world! No wonder there is such creative energy here! In this section we are going to look at how modern humans gradually developed over millions of years from hominids, or “human-like” creatures.
Over the time human body has changed quite a lot. Evolution is the theory that tries to explain how simple how simpler forms of life “evolve “to become more complex. We do not know everything about human evolution. But we do know that human-like hominids first emerged from the ape family about 5 million years ago. These creatures were more ape-like than humans and lived in the open. Over millions of years they learned to walk upright and developed bigger brains.
FORMATION OF METAMORPHIC ROCKS
FORMATION OF METAMORPHIC ROCKS:
Metamorphic rocks are rocks that have "morphed" into another kind of rock. These rocks were once igneous or sedimentary rocks. How do sedimentary and igneous rocks change? The rocks are under tons and tons of pressure, which fosters heat build up, and this causes them to change. If you exam metamorphic rock samples closely, you'll discover how flattened some of the grains in the rock are.
Schist rocks are metamorphic. These rocks can be formed from basalt, an igneous rock; shale, a sedimentary rock; or slate, a metamorphic rock. Through tremendous heat and pressure, these rocks were transformed into this new kind of rock.
Gneiss rocks are metamorphic. These rocks may have been granite, which is an igneous rock, but heat and pressure changed it. You can see how the mineral grains in the rock were flattened through tremendous heat and pressure and are arranged in alternating patterns.
GRAVITATIONAL FORCE
DID YOU KNOW THAT: Objects fall to the ground as a result of the attracting force between earth and the object? Newton was the first person to establish this fact. It has been known since earliest times that falling bodies undergo accelerated motion. The Greek philosopher, Aristotle (384 – 322 B.C.), maintained that heavier objects fall faster than lighter objects. He had no experimental proof for this incorrect statement. He also stated that objects fell to the ground and that clouds rose up to find their “natural position”. These doctrines were accepted for many centuries until the invention of the cannon stimulated further research about the motion of falling bodies and projectiles. Galileo (17th century) was the first person to investigate Aristotle’s statement by means of experiment. He climbs up the leaning tower of Pisa with a piece of great mass and light objects like fluff, chicken feather et cetera. He drops them simultaneously from the same height above the building. He realized that air resistance influenced the falling of light object, feather and fluff, and water droplets in clouds to a large extent.
Although Sir Isaac Newton’s discovery of the Law of Universal Gravitation represents one of the greatest scientific achievements of all times, he was led to this discovery partly by the work of early astronomers and partly by his own remarkable insight into the laws of nature. It is said that Newton began speculating about gravitational forces when he noticed an apple fall to the ground. He knew that the apple fell because of the earth’s gravitational force of attraction, but then it occurred to him that the apple might attract the earth or that one apple might attract another, he extended this concept and considered that there might be gravitational attraction between all heavenly bodies.
Since objects accelerate towards the earth, it follows that the earth exerts an attracting force on them. According to Newton’s third law of motion the objects must, however, also exert a force of the same magnitude on the earth, but in opposite direction. Newton then deduced that any two objects in the universe exert a force of attraction on one another. Newton called this mutual force of attraction gravitational force (or the force of gravity).
This blog is about Newton's Law of Universal Gravitation. Learners are exposed to the nature and effects of Gravitational Force as it acts on heavenly bodes. The Web site will cover the task, the process, assessment and contents of the lesson plan for the 12th grade in Physical Sciences.
Although Sir Isaac Newton’s discovery of the Law of Universal Gravitation represents one of the greatest scientific achievements of all times, he was led to this discovery partly by the work of early astronomers and partly by his own remarkable insight into the laws of nature. It is said that Newton began speculating about gravitational forces when he noticed an apple fall to the ground. He knew that the apple fell because of the earth’s gravitational force of attraction, but then it occurred to him that the apple might attract the earth or that one apple might attract another, he extended this concept and considered that there might be gravitational attraction between all heavenly bodies.
Since objects accelerate towards the earth, it follows that the earth exerts an attracting force on them. According to Newton’s third law of motion the objects must, however, also exert a force of the same magnitude on the earth, but in opposite direction. Newton then deduced that any two objects in the universe exert a force of attraction on one another. Newton called this mutual force of attraction gravitational force (or the force of gravity).
This blog is about Newton's Law of Universal Gravitation. Learners are exposed to the nature and effects of Gravitational Force as it acts on heavenly bodes. The Web site will cover the task, the process, assessment and contents of the lesson plan for the 12th grade in Physical Sciences.
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