What is Energy – Resources of Energy

Introduction to Energy

Key Concepts

1. What is energy
2. Why do we need energy
3. When can we say that an object has the energy?

Introduction

What is energy? 

Have you ever thought about what happens in the street light when it glows, what makes vehicles move, musical system when it has songs playing? 

In street light, it is light energy. In vehicles, it is mechanical energy, and in the sound system, it is sound energy. 

Energy is standard in all these situations.  

Explanation

But what is energy? 

Definition: In physics, energy is regarded as the capacity to do work. In general, energy is the utility of the body to do some work like moving, heating, etc. 

Energy is represented by E, and the unit of the energy is Joules in the SI system. 

Energy resources: 

1. Renewable energy 

2. Non-renewable energy 

Renewable energy  

Renewable energy is sometimes called ‘clean’ energy, it is from nature, and it is ‘on-depleting’ and can be used again and again. 

Non-renewable energy: 

The energy which is not used again and again and depletes once used are called a non-renewable energy source. 

Why do we need energy? 

Situation: 

Let us consider a restaurant which serves food to its customers daily. The restaurant makes food to meet the need of the customers. 

Can you say what type of energy they need to prepare food for the customers? 

Can you list out various forms of energy resources that are used by the restaurant to meet its needs?  

The restaurant needs: 

1. Light energy to prepare food as they cannot prepare food in the dark. 

2. The heat energy to prepare food in time. 

3. Muscular energy to prepare raw materials and another service. 

4. The electric energy for the working of the machinery. 

We need energy: 

We all need the energy to do our daily works without interruption. Everything on the earth possesses energy; hence, all the objects on the earth have some energy or wants at some point to do work. 

Energy is not only on the Earth but in space also. Every object has energy. 

E.g., Earth rotates around the Sun due to the energy and the light and heat from the Sun reaching the Earth from space. 

When can we say that a body has the energy? 

We can say that a body has energy when there is a useful work outcome. 

Energy is regarded as the capacity to do work. 

Example: 

Let us consider a block lying on the floor. The block is at rest and not moving in any direction. We can say that the block has no energy as the block is not doing any work. It is at rest. 

Now, person A is moving the block from one place to another place, where the person needs to have the energy to move the block from one place to another. 

Therefore, we can say that the block and person A both possess energy as the person is using the energy to move the block from one place to another as useful work. 

Summary:

What is energy?

Definition: In physics, energy is regarded as the capacity to do work. In general, energy is the utility of the body to do some work like moving, heating, etc.

Energy is represented by E, and the unit of the energy is Joules in the SI system.

We need energy:

We all need the energy to do our daily works without interruption. Everything on the Earth possesses energy. Hence, all the objects on the Earth have some energy or want some energy to do work.

• Energy is not only on the Earth but in space also.
• Every object has energy.
  When can we say that a body has the energy? We can say that a body has energy when there is a useful work outcome.
• Energy is regarded as the capacity to do work.