What Is energy Playing soccer takes a lot of energy You need energy to run and to kick the ball All that activity may make you feel hot Heat itself is a form of energy Energy is another word for power It makes things move machines work and living things grow There are many forms of energy including chemical energy sound energy electrical energy light energy and heat energy Heat energy is also called thermal energy Each of these forms of energy can do work All forms of energy can be described as either potential energy or kinetic energy Potential energy is stored energy An object Every time your body moves you are generating heat energy 4
Can you think of other examples of potential and kinetic energy with potential energy has the ability or potential to move Kinetic energy is the energy of moving things All moving objects have kinetic energy Think About It Which of the forms of energy named on page four can be described as potential energy Which can be described as kinetic energy 5
Chemical energy stored in this toy car’s batteries changes to electricity which powers the car Energy can also transform or change from one form into another With the use of a battery stored chemical energy can change into electric energy In a lightbulb electric energy changes to light and heat In fact heat is often produced when energy changes forms One way heat is produced is through friction Friction is a force that acts between two objects that are in contact with 6
one another It slows or stops movement between the two surfaces that are touching The two objects require more moving energy called mechanical energy to work against the friction force As the moving mechanical energy works against the friction it transforms into heat energy For example you may have noticed that when you rub your hands together the motion warms your hands and you Vocabulary Mechanical energy is all the energy an entire object has because of its motion and its position or its potential energy plus its kinetic energy The faster two objects rub against each other the more heat energy is generated 7
