Force and Energy
Concept: Energy—Types and Conversion
What is Energy?
- It is defined as the capacity to do work. In terms of an object, too, it is measured as its ability to accomplish a work.
- The unit used to measure energy is Joule.
- 1 Joule is defined as the energy required to do 1 Joule of work.
Law of Conservation of Energy:
The law of conservation of energy states that—Energy can neither be created nor destroyed; it can be transformed from one form to another.
Types of energy based on their source:
Different forms of energy:
- Kinetic energy:
- Potential energy:
The energy possessed by a moving object or the energy possessed by an object due to virtue of its motion is called kinetic energy.
Examples: A running man, a kite in the air, and an aircraft in motion possess kinetic energy.
Kinetic energy increases and decreases with respect to the motion of the objects.
It is defined as the energy stored in an object due to its position relative to the other objects.
- Stretched rubber band
- Water stored in the dam.
- A stone tied or kept at a height.
Mechanical energy is defined as the energy present in an object due to the virtue of its motion and position. In simple words, it can be defined as the sum of both kinetic and potential energy.
- Using a sewing machine to sew cloth.
- Moving of a fan in a circular motion when switched on.
- It is the only form of energy that can be seen.
- Light energy is a form of kinetic energy i.e it is produced by moving light rays that reach us.
- Light energy can be produced by both natural and artificial sources.
Examples: Light from the sun, light from a bulb or candle.
- Heat energy is also called thermal energy. It is also a form of kinetic energy.
- All matter is composed of atoms and molecules. When these molecules are heated, they start moving or vibrating vigorously, which leads to the production of heat.
Examples: Heat from burning coal, heat from the earth’s interior, heat from the sun.
- Electrical energy is produced by virtue of electrons.
- Electrons are the subatomic particles that would be discussed in higher classes.
- Electrons flow in a particular direction to produce electrical energy.
- Electrical energy can be generated from various sources.
- This form of energy is produced when a substance vibrates.
- Vibrating substances produce waves that travel in a medium. This medium can be a solid, liquid, or gas.
- Sound cannot be heard in space because of the absence of a medium.
- Sound is produced when we sing, talk, clap, etc.
- The energy stored in any substance by virtue of its nature and composition is called chemical energy.
- Energy stored in food.
- Energy stored in a dry cell.
- Energy stored in wood.
- Energy stored in an LPG cylinder.
- The chemical energy can be directly used or first converted into other forms and then used. For instance, chemical energy in wood is converted into heat energy for its use.
- It is also called atomic energy.
- It is produced due to the splitting or combining of atoms and subatomic particles.
- Nuclear energy has wide industrial use these days.
- Nuclear energy is produced in enormous amounts and is monitored and controlled carefully.
- Energy from the sun is termed solar energy.
- It is harnessed and converted in various forms for proper use.
- Plants perform photosynthesis which converts solar energy into chemical energy (food).
- Solar cells harness solar energy and convert it into electrical energy.
- The energy possessed by moving air is called wind energy.
- Wind energy is harnessed and used to produce electrical energy, which is used for various purposes.
Conversion of energy:
- Energy can be converted from one form to another using various means. Some of the examples are given below—
Harnessed: To control and use the energy of something.
Subatomic: The constituents of an atom, i.e., proton, neutron, and electrons.
Did You Know?
- Even when we are asleep, our body uses energy to regulate the heart and maintain the blood flow throughout the body.
- The chemical sources of energy like coal and petroleum can finish one day. Scientists are working on alternative fuels which could be used in the future.
- Most forms of energy are either kinetic or potential.
- The USA's Mojave Desert is home to the world's largest solar power plant.
- During a chemical reaction, the energy produced is transformed into heat or light.