1. Energy is needed to carry out life process.
2. Energy is also needed to do our daily chores.
3. Energy comes from many sources.
4. The main source of enegy is the sun.The sun give us unlimited energy.
5. There are many form of energy.
6. Forms of energy : Light,Heat,Sound,Chemical,Kinetic and Electric.

1. The energy that can be replenished when used up is known as renewable energy.
2. The energy that cannot be replenished when used up is know as non-renewable energy.

• Solar
• Wind
• Biomass (for example :wood and grass.

• Petroleum
• Natural gas
• Coal and charcoal

TIPS

• The Solar System consists of the Sun, planets, natural satellites (moon), asteroids, meteoroids and comets.
• The Sun is the largest object that gives out its own light and heat in the Solar System. It is the only star in the Solar System.
• A planet is a large object that moves around the Sun and does not give out its own light. It reflects the sunlight that falls on its surface.
• The planets, with increasing distance from the Sun, are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto.
• Asteroids are small rocky bodies that orbit the Sun.
• Meteoroids are small rocky particles that orbit the Sun. It is much smaller than asteroids. Meteors that reach the ground are called meteorites.
• Comets are small, rocky, icy bodies that orbit the Sun.

TIPS

• Objects made of iron or steel can rust.
• Two factors that cause rusting are air and water.
• If any one of these two factors is absent, then rusting cannot take place.
• Rusting can be prevented by keeping objects made of iron or steel away from air and water. Example: applying grease or oil to the surface of an iron or steel object prevents air and water (moisture) from reaching the surface.

COMMON MISTAKES

The figure below shows an investigation.

What happens after a week?

1. The mass of the nail decreases
2. The nail turns reddish
3. The water changes colour
4. The nail has no change

The correct answer is B

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