P6 Science Forms of Energy

Energy is the ability to do work. The food that we eat gives us the energy to do work. Food is a source of energy. The Sun is the most important source of energy. It provides the energy that all living things need in one form or another.

Kinetic Energy or Movement Energy

1. The energy that a moving object has because of its motion is called kinetic or

movement energy. All moving objects have kinetic energy. The faster the

motion, the more is the kinetic energy. Examples include wind, rolling ball and a

moving car.

2. For objects of the same mass, the one that moves faster has more kinetic energy.

3. For two objects moving with the same speed, the one with the greater mass has

more kinetic energy.

4. Kinetic energy of an object depends on its mass and on the speed the object moves.

6. If mass increases, kinetic energy increases. If the speed of the object increases,

the kinetic energy also increases.

Potential Energy or Stored Energy

1. The energy that an object has because of its position or condition is called

potential or stored energy.

2. There are three main forms of potential energy namely :

a. gravitational

b. chemical

c. elastic

Gravitational Potential Energy

1. An object that is raised to a high point above the ground has gravitational potential

energy.

A ball placed at a point above the ground has gravitational potential energy

2. Gravitational potential energy depends on :

a. mass b. height

3. The higher the object is, the greater is its gravitational potential energy.

4. When two objects are at the same height above the ground, the object with more

mass has more gravitational potential energy.

5. The higher and heavier an object is, the more the gravitational potential energy it

has. For example, a skier who begins his ski from a high position finds himself

possessing much gravitational potential energy. When he skis, he moves down the

slope at a high speed.

Chemical Potential Energy

1. The energy stored in food, fuel and battery is chemical potential energy.

Elastic Potential Energy

2. Elastic potential energy is also present when we stretch object like the rubber band

and wind object like the spring.

3. When we stretch the rubber band, we change its original condition and we transfer

our energy to it. The more we stretch the rubber band, the more elastic potential

energy it has. When we let go of the stretched rubber band, it either returns to its

original shape or releases all its elastic potential energy by changing into movement

energy, also known as the kinetic energy, which had been discussed previously.

4. When a wound-up spring in the toy car unwinds, the potential energy changes into

kinetic energy, making the toy moves. The more wound-up the spring is, the more

is the elastic potential energy.

5. A bow is made of a long piece of wood bent into a curve by a string attached to its

two ends. When we use the bow, we arm the bow with an arrow and pull the string

backwards to bend the bow fully. As a result, elastic potential energy is stored in

the bow. Thus, when we release the string, the bow springs back to its original

position. The elastic potential energy stored in the bow is transferred to the arrow

as kinetic energy and the arrow shoots forward immediately.

Heat Energy

1. Heat energy is given out by hot objects or burning objects. It is the form of energy

that can cause an object to change its temperature or state.

2. In the house, heat is used for cooking, ironing, drying things and warming the

rooms.

3. Heat in the industries is used for welding and extracting iron from its ore.

4. Plants make use of heat energy from the Sun to make food and animals obtain their

energy either directly or indirectly from the plants.

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