Energy transformation

Potential and Kinetic Energy

All matter has energy. Two of the most basic kinds of energy are Potential and Kinetic energy.

Potential Energy is energy at rest, yet having the ‘potential’ to do work in that state. Examples include the potential for a stationary rock to fall from a height or for stored water behind a dam to flow to a lower position.

Kinetic Energy is the energy of movement. A bullet fired from a gun, a moving train, a high-speed electron lighting the TV screen, all are forms of kinetic energy.

There are Many Other Forms of Energy

There are many forms of energy we see or use in our daily lives –

1. Thermal energy in the form of heated particles in objects
2. Radiation energy in the form of Electromagnetic waves which we get from the sun
3. Chemical energy from fuels used to run our cars and machines
4. Electrical energy which powers our batteries and lights our homes
5. Atomic energy which comes from splitting atoms, used in nuclear power plants and nuclear submarines
6. Sound energy made by vibrating objects such as whistles, horns and musical instruments
7. Mechanical energy produced by objects in motion such as bicycles, pulleys and exercising

A light bulb transforms electrical energy into heat and light energy.

Energy can be transformed from one form to another. When stored water is released from behind a dam, potential energy gets converted into kinetic energy due to the motion of water. When this moving water turns a turbine, its kinetic energy is transformed into electrical energy.

A pebble released from a catapult is also an example of potential energy transformed into kinetic energy. When the pebble strikes a target this kinetic energy is transformed into sound and heat energy.

Here are some more examples of energy transformation –

1. Stored chemical energy in batteries is transformed to light energy in a flashlight
2. Pulleys and levers used to lift objects are converting mechanical energy into potential energy
3. Solar panels convert light or solar energy into electrical energy to power our homes and even solar calculators
4. Chemical energy in fuels is transformed into mechanical energy to run our automobiles
5. Chemical energy in gunpowder is transformed into kinetic energy of the moving bullet
6. Solar energy falling is transformed into chemical energy during the photosynthesis process in plant cells
7. Our bodies convert chemical energy obtained from food into mechanical energy to move and perform activities

Energy Loss

If it weren’t for friction, a rolling ball would have rolled forever. However, there is always friction in the form of rubbing surfaces or air resistance that will slow an object down. When energy is converted from one form to another, some of the input energy is always converted into a non-functional form of energy such as heat. This is known as Dissipation. It is still a form of energy but it is energy in the form of heat that is of no use.

Similarly, when chemical energy is transformed into mechanical energy to operate an engine, some of this energy may be lost in the form of vibration of the engine, which is useless kinetic energy, and some energy may also be lost as sound energy.

Check Point

1. Which of these are forms of energy –
   1. Mechanical
   2. Sound
   3. Chemical
   4. Thermal
   5. All of the above
2. A rock toppled down from a cliff converts ______ energy into ______ energy.
3. A pulley used to lift an object converts ______ energy into ______ energy.
4. ______ energy in fuel is transformed to ______ energy to run an automobile.
5. The process of energy lost due to heat or sound is referred to as ______.

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