Electricity Has Many Uses

Electricity Has Many Uses

Devices that use electricity change electrical energy into other types of energy such as light or heat.

A computer changes electrical energy into light, sound and heat.

Many devices have electrical motors. Electrical motors are machines that change electrical energy into energy of motion.

Multiple Choice

Bottom of page 519. A light bulb produces heat and light. Why would an engineer want to reduce the amount of heat a light bulb produces.

• So people can touch it.

• To conserve (save energy).

• To make it less bright.

A magnet is an object that attracts iron and a few other metals.

Magnetism is a physical property of matter. Magnets push and pull because of their magnetic field.

A magnetic field is the space around the magnet where the force of the magnet acts.

A magnet has two ends or poles. A pole is the part of the magnet where it's magnetic field is strongest. One pole is called the south pole and one pole is called the north pole.

Two north poles are alike. If you put them near each other they will repel each other. The same for two south poles together.

A north and a south pole near each other will attract or pull each other together.

Multiple Choice

How is the top magnet floating above the bottom magnet?

• The magnets that are facing each other have the same poles.

• The magnets that are facing each other have the opposite poles.

Multiple Choice

What happens when two magnets with the same poles are near each other?

• They attract each other.

• They repel each other.

Multiple Choice

What happens when two magnets with different poles are near each other?

• Attract each other.

• Repel each other.

Multiple Choice

Why don't the paper clips fall due to gravity?

• The paper clips are magic.

• The magnet conducts electricity so the paper clips don't fall.

• The magnetic field of the magnet is strong enough to hold the paper clips through his hand.

If you coil a wire around an iron nail and connect both ends of the wire to a battery then you will turn the piece of metal into an electromagnet.

A device in which electric current produces magnetism is called an electromagnet.

Electromagnets are used in junkyards to move heavy pieces of metal.

Today, every electric motor contains at least one electromagnet. You can find electromagnets in telephones, doorbells, speakers and computers

A generator is a device that converts mechanical energy into electrical energy.

Some generating stations use renewable resources like falling water, wind, sunlight to convert into electrical energy.

Some generating stations use nonrenewable resources like oil. gas, coal to convert to electrical energy.