What Is energy Energy is another word for power It is one of the most basic ideas in science A simple definition of energy is the ability to do work Energy makes things move It makes plants and animals grow and it makes machines work All activity in the universe can be explained in terms of energy and matter Energy is important but it can be a bit complicated to understand Vocabulary Anything that takes up space is called matter Plants absorb energy from the sun and then use that energy to grow
The food that we eat gives us the chemical energy we need for our bodies to do work That is because energy exists in many different forms Some of the forms of energy are heat light electrical energy chemical energy mechanical energy and sound energy We encounter these forms of energy in our life every day For example the food we eat contains chemical energy Most cars trucks buses and motorcycles run on the chemical energy that is stored in gasoline 5
Think About It How might other forms of energy be converted into heat energy One form of energy can change into another form of energy In a lightbulb for example electric energy changes to light and heat When you burn a piece of wood in a campfire or a fireplace the chemical energy of the wood changes to heat and light Our bodies get the energy they need to grow move and think from the chemical energy stored in the foods we eat Batteries also contain stored chemical energy When you use batteries in a flashlight the chemical energy from the batteries is changed into electricity and then into light Batteries store chemical energy which can change into electricity 6
Burning wood converts chemical energy into heat energy and light energy The fact that one form of energy can convert or change into another makes it easier for people to get the energy they need If people need light they can convert the chemical energy in candles into light energy Or they can convert the electricity running to a lamp into light 7
