Fossil fuel and electcrity:

fossil fuels are plants and animal matter from long ago,that was buried under mud and sand and eventually became coal.

we burn the coal to make thinds like petrol , disel , oil to obtain the energy that is realised from them.

Another thing is power stations are built near coal mines beacause it is expensive to take coal long distance.

Coal is a fossil fuel . It was formed from plants many millions of years ago when they trapped and stored energy from the sun. that same energy is released when we burn the coal.

Coal-fired power stations use the energy from burning coal to heat water to steam in a boiler that steam flows at a high pressere around a turbine made of metal blades that turn like a propellar. Steam must enter the turbine witch drives a generator,which is a machine that produces electricity. these generators are huge. Fossil fuels are also non renweable whch means the can not be replaced and will run out but we are begining to use renewable energy such as solar,wind and hydropower because soon some time in the future we will not have fossil fuels.

Also electricty is expensive because it requires a lot of electrical infrastructure to generate it and get it to you. power stations ,coal mines, turbines and generators and power lines are very expensive.

A pylon is a large thing that looks like a pole supporting electrical cables.

Infrastructure is things like roads,drains,pylons,power lines and power stations that a country or community needs.

Hydropower-energy from falling:

We can use flowing water to generate electricity. This is called hydroelectric power.

Gravity is the force that pulls the water downwards. The water moves through a large pipe to a turbine. The water falls on the blades of the turbine and turns it. The turbine then turns the machine that generrates electricity. whitch is the generator. The only damage this power plant makes is when doing construction it can damage the environment, and preventing fish from moving freely after the power plants are constructed .

Solar energy:

The sun is our most important source of energy. It gives the earth a continuous and renewable supply of energy. We can use that energy to heat water using solar panels on roofs, We can also use a different sort of panel that converts solar energy direcly into electricy. One limitation of solar energy is that it only works when the sun is shinning. Scientistes are woking on a way to store that energy.

wind energy :

When strong winds blow regularly,they can be used as a source of energy. There are some disadvantages of wind power ,birds sometimes fly into the blades and the wind farms can be noisy. However, modern designs have minimized both of these problems. The wind doesn’t always blow, but a good electrity system in a country will have many different types of power genration, so that they work with each other.

The sun, planets and asteroids:

The solar system has many planets and their moons and other objects that revolve or obit around the sun. A planet is a round , mostly cool ball of rock like the planet earth that we live on or a gas ball like jupiter. In this topic you will learn about astroids also. witch are thousands of little pieces of rock and small stones all orbiting in a area where a planet could have been put.

The sun is a star in the center of the solar system. And because it’s so huge it has very strong gravity. In the early stages of the solar system forming the matter that was around the sun did not fly away into space , but started moving around it , held there by the sun’s gravity. That matter formed into planets and some of the planets have moons moving around them.

Orbiting the sun:

There is eight planets and the asteroid belt in orbit around the sun.

When all the planets were forming millions of years ago there was one extra planet that might have formed between Mars and Jupiter. But because of the strong gravity from those two planets it was disturbed and instead formed thousands of little pieces of rock and small stones called asteroids. These astroids now orbit in a zone where that planet might have been. We call that zone the asteroid belt .

Key words:

asteroid - Small rocks that orbits the sun in a zone between Mars and Jupiter {the asteroid belt}

Gravity - all objects even small ones have gravity and gravity is a force that pulls on other objects. But we normally think of gravity only in terms of large objects like planets , moons and stars.

moon - a large natural large object that orbits around a planet.

planet - a round , mostly cool ball of rock like planet earth that we live on or gas ball like Jupiter and Saturn.

revolve - move around something else in an orbit {the same meaning as orbit}

Solar - to do with the sun

Solar system - all of the planets moons and other objets that move around the sun.

atmosphere - the layer of gas around a planet for example the air around the earth.

gas giant - a planet that is not solid but mostly made of gas

Each planet has its own composition and number of moons:

Planet composition :

We call the first four planets the inner planets because the are closer to the sun. The other four are called the outer planets. the inner planets are rocky like earth but the outer planets are mostly huge balls of gas. This is why we call them gas giants. They are mostly atmosphere with small rocky cores.

Plant moons:

Earths moon has no atmosphere. Some planets have many moons. These moons have names. Only two planets in our solar system have no moons and they are Mercury and Venus.

Moons do not give out their own heat and light:

The moon is a cold and rocky object. It has no way of producing and giving out heat and light. The moon does not burn like a star. But we can see the moon. This is because we see the sunlight that shines onto the moon. That light is then reflected off the moon , witch means the light bounces off. or you can say the sunlight falls onto one side of the moon witch is the side we see.

What we can see on the moon:

On the moon we can see craters lighter areas that are mountains and darker areas that are flat plains. The moon also has some higher areas and some lower areas on it . The light colored areas that we can see are the higher ones. We call these highlands.

There were lots of asteroids flying around the solar system when the solar system was forming. They hit the moon many times forming round shapes called craters. A crater is a hole caused by something that hit there very fast and hard. The lines spreading away from them are the rocks and dust that were blasted out of the center. We call these rays. Later lava from under the moon’s crust started erupting. The lava flowed into some of the lower areas. The lava was made of darker coloured rock. Early astronomer’s thought these darker areas were made of water and called them seas. They are not seas , but lower lying flat plains. They have fewer craters because they are younger and the main asteroid bombardment happend earlier.

Key words:

reflect - to bounce off , like light or sound bouncing off something and going in the opposite direction.

Crater - a round basin shape caused when a large object like an asteroid crashed into the moon.

Rotation of the Earth:

Our solar system includes eight planets that all move or revolve around the Sun. Each of these these planets also rotates or spins on it’s own axis.

Planets were made from huge clouds of gas and dust. This gas and dust was swirling around in the solar system. This made the planets spin.

Key words:

Revolve - To follow an orbit or to travel around the outside of a circle

Rotate - To spin around on an axis

Planet Earth is rotating or spinning. Earth takes about 24 hours to complete one rotation. One day is 24 hours long. In this time we experience 12 hours of daylight and 12 hours of darkness or night.

The earth revolves around the sun. We have day and night because the earth is rotating.

1. South Africa's Contributions to Astronomy

• SALT: Southern African Large Telescope

• KAT: Karoo Array Telescope (KAT-7)

• SKA: Square Kilometre Array

Key Information:

• SALT: One of the world’s largest optical telescopes, located near Sutherland.

• KAT-7: A radio telescope in the Karoo, consisting of seven receiver dishes.

• MeerKAT: Expansion of KAT-7 with 64 dishes.

• SKA: An international project with thousands of dishes across continents.

  • Will be 50 times more powerful and 10,000 times faster than other telescopes.

  • Combined surface area of 1 square kilometer.

  • Scientists worldwide have booked time to use MeerKAT (500+ international astronomers and 58 from Africa).

Advantages for South Africa:

• Leadership in cutting-edge radio astronomy.

• Technological advancements and scientific contributions.

• Attracts international collaborations and investments in science.

2. Mars Exploration and the Mars Rover

Mars:

• Known as the Red Planet, located 225 million km from Earth.

• Future plans: Human missions to Mars by mid-2030s.

Mars Rover Missions:

• First spacecraft landed: 1976.

• Rovers:

  • Spirit and Opportunity: Sent in 2004.

  • Curiosity: Sent in 2011.

• Functions:

  • Conducts experiments using mechanical arms.

  • Takes soil and rock samples.

  • Powered by solar cells.

  • Includes instruments to detect signs of water and life.

  • Sends data back to Earth via antennae.

Scientific Goals:

• To determine if Mars has water or life.

• Collect environmental data, such as weather patterns.

Key Vocabulary:

• Optical telescope: Gathers light to observe distant objects.

• Radio telescope: Captures radio signals from space.

• Astronomer: Scientist studying space.

• X-ray: A type of radiation emitted by stars and space objects.

The Planet Earth's Rotation

• Earth takes about 24 hours to complete one full rotation.

  • One day is 24 hours.

• We experience 12 hours of day and 12 hours of night due to Earth's rotation.

• If the Earth did not rotate:

  • One side of the Earth would become extremely hot.

  • The other side would become very cold.

Revolution of the Earth

• All the planets orbit the Sun in a pathway called an orbit.

• Some planets, like Mercury and Venus, have shorter orbits because they don’t need to travel as far to complete one orbit around the Sun.

• Earth revolves around the Sun in its own orbit or pathway, which takes 365 ¼ days to complete one revolution.

The Moon

• The Moon has two main movements: rotation and revolution.

  • The Moon rotates on its own axis, just like the Earth.

  • While the Earth rotates once in 24 hours, the Moon rotates once in about 29 days.

• The Moon also takes about a month to revolve around the Earth.

  • Its revolution follows a pathway or orbit around the Earth.

  • This means that the Moon rotates and revolves in the same amount of time, keeping the same side facing Earth.

• The Moon revolves around the Earth, and both the Earth and Moon together revolve around the Sun.

• Our moon can be seen from earth because the sun's light reflects off the moon.

Telescopes

• Telescopes are used to look into space and gather information from space objects.

Early Telescopes

• The first telescopes were invented about 400 years ago.

• Using one of these early telescopes, Galileo Galilei discovered some of Jupiter’s moons in 1610.