Energy Facts

I. Forms of Energy

II. Static Electricity & Lightning

III. How Does Electricity Flow?

IV. How Does Electricity Get to Your Home?

V. Electricity & Magnetism

I. Forms of Energy

Energy is the ability to work. You need energy to force an object to move. You need energy to make matter change. The blowing wind, the warm Sun and a falling leaf are all examples of energy in use. Energy makes motion and change possible.

There are two basic types of energy, kinetic and potential. Kinetic energy is being used as an object is in motion. Potential energy is in storage just waiting to be used. Many things start out having potential energy, and then once they begin to move, the energy becomes kinetic. For example, a car parked in a driveway has potential energy. When the ignition is started and it drives away, the car gains kinetic energy as it moves. Can you think of another example of potential energy turning into kinetic energy?

Energy is captured in many different forms:

Electrical energy is the movement of charged particles, negative (-) and positive (+). It can come from batteries or power plants and it can also be found in nature. Power plants burn fuel to make electricity which is then sent to homes and businesses through wires.

Chemical energy is stored in the particles that make up food, fuel and other matter. The food you eat gives chemical energy which allows you to walk, run and move.

Light energy comes from the Sun. Plants use it to make food and scientists use it to create lasers.

Mechanical energy is matter in motion. An airplane soaring through the sky has mechanical energy just like the wind or a flowing river. Sound is another type of mechanical energy.

Thermal energy comes from the motion of tiny particles in matter. The faster the particles move, the warmer the matter can get. Examples of thermal energy are stoves and matches.

Nuclear energy is formed when tiny particles called atoms split apart (fission) or join together (fusion). The Sun’s energy is produced from nuclear reaction.

II. Static Electricity & Lightning

Electrical charges can be negative (-) or positive (+). Opposite charges attract each other while similar charges repel each other. As electrical charges build up on a material, it creates static electricity.

Have you ever walked across a carpet and then touched a doorknob and got a shock? That is an example of static electricity. Can you think of another example?

A powerful example of static is the lightning bolt. Lightning is a discharge of static electricity from thunderclouds. Inside the cloud, water and ice rub together and separate positive and negative charges. The positive ice particles are lightweight and gather at the top of the cloud. The heavy negative water particles settle at the bottom until the buildup is so great the charge tries to jump to the ground where particles on the ground are positively charged. This jump emits a giant spark or lightning bolt. A single bolt has the power to light 100 million light bulbs!

To keep safe from lightning, stay away from high places and tall objects (hills or trees). Get out of the water and don’t touch electrical devices or any metal objects. For more safety tips, visit the Power Kids safety section.

III. Electricity

In order for electricity to flow, it must follow a complete path through a circuit. A circuit starts at the source of the electricity and ends at an output device where the electricity is used or released. A switch controls the current as it flows through the circuit. For example, a circuit can start at a battery (source) and flow through a copper wire and a switch until it reaches a light bulb (output device) and back again to the battery.

The electricity that flows through a circuit is current electricity. It can only flow through closed circuits, meaning there are no gaps or breaks in the path. A broken path is called an open circuit.

Electrical current is measured in units called amperes. It is measured in amps.

IV. How Does Electricity Get to Your Home?

The electrical current that flows to your home is known as alternating current (AC) because it moves back and forth. AC is produced by a generator at a power plant as it changes mechanical energy to electrical energy. Generators use turbines to spin a coil around a magnet. Most turbines are turned by steam that comes from burning fossil fuels (coal, oil, natural gas). The rising steam turns the blades of the turbine. Wind or water controlled by dams can also be used to power the generator’s turbine.

The electrical current produced at the power plant then travels to a transformer where the voltage is increased. Voltage is the force or pressure that moves electric current through a conductor. It is measured in volts. High-voltage current is good at traveling long distance along power lines, but it is too dangerous to use in your home. So the current stops another transformer where the voltage is decreased. The voltage is decreased one more time at a transformer near your home. By then the current’s voltage is low enough and safe enough to enter your home and power your appliances.

For even more details about how electricity gets to your home, visit the Power Kids Distribution of Electricity diagram.

V. Electricity & Magnetism

Electricity is very closely related to magnets. A magnet is a material that attracts other objects containing the elements iron, nickel or cobalt. All magnets have two ends, called poles. One pole is the magnetic north pole, and the other is the magnetic south pole. The pull of a magnet is strongest at its poles. Opposite poles attract each other and similar poles repel each other (remember how positive and negative electrical charges attract and repel?).

As electrical current flows through a wire, a weak magnetic field forms around the wire. The magnetic field can be made stronger if the wire is coiled around an iron bar. As the electricity flows, it creates a temporary magnet called an electromagnet.

Electric motors are electromagnets in use. They transform electrical energy into mechanical energy using magnets and a coil of wire.