What is Energy?

Описание: energy #work #ngscience
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What exactly is energy? Let's find out!
Energy is all around us. We cannot see energy, but we can see the things that energy does. Energy makes things move. It powers the machines we use. It can make things get hotter or produce sound. Energy is used to light up our homes and cities and power the vehicles we use.

All organisms need energy to grow, reproduce and carry out life processes. Plants use the light energy from the Sun to make food in the form of sugar. This energy is passed to animals and people when they eat plants and other animals.

Scientists define energy as the ability to do work or cause change. The work or change caused by energy can be measured and observed.

Forms of Energy
Energy cannot be made and cannot be destroyed. It exists in many forms and can be transformed from one form to another. Let’s take a brief look at some forms of energy.

Kinetic energy is the energy of movement. A car speeding along a motorway has kinetic energy. The faster the car moves, the more kinetic energy it has.

An object does not have to be moving to have energy. An object can have energy due to its position or structure. This energy is called potential energy. A roller coaster car at rest at the top of a track has potential energy. The potential energy is converted to kinetic energy when the car speeds down the track.

All matter is made up of tiny particles. The movement of these particles is called thermal energy. All objects have thermal energy. The faster the particles in matter move, the more thermal energy it has.

Chemical energy is energy that is stored. It is a type of potential energy. Energy is released when chemical reactions take place. Food is a form of chemical energy. When we eat food, a chemical reaction converts the chemical energy into kinetic energy that enables us to move about, keep warm and carry out life processes.

Fuels such as gasoline, coal, gas and wood have chemical energy. A chemical reaction occurs when the fuels are burned and light and heat are released.

Electrical energy is generated by the movement of charged particles – electric current. Electrical energy is very useful to people as it allows energy to be moved from place to place or be converted into other forms of energy.

Light energy is a form of energy that travels in magnetic and electric fields. Visible light is the only form of energy that we can see. The light from the Sun is our most important source of light energy.

Sound energy is caused when something vibrates. The vibrations travel in waves. We hear sounds when sound waves reach our ears.

In this chapter, we are going to take a closer look at two types of energy – thermal energy and light.