An introduction to insulators and conductors By Encyclopaedia Britannica, adapted by Newsela staff on 01.21.20 Word Count 697 Level 830L

Image 1. Workers climb an energy tower to remove a glass insulator on the outskirts of Mendoza, Argentina, in 2003. They will replace the old insulator with a new, organic one. Photo by: Daniel Garcia/AFP/Getty Images)

When an electrical current travels along a power line, it's thanks to two types of materials: conductors and insulators.

Materials that conduct electricity, like the aluminum wire inside the power line, are known as conductors. They allow electricity to travel for long distances.

A material that does not conduct electricity, like a rubber coating around a power line, is known as an insulator. An insulator stops the electricity in its tracks. It keeps the electricity from flowing away from the power line. It also makes it possible to install and handle the line without getting a shock.

Conductors and insulators are also important in the flow of heat. Conductors allow heat to pass through them easily. Insulators, on the other hand, block the flow of heat.

Insulators and conductors have many uses in everyday life.

Metals Are Good Conductors

This article is available at 5 reading levels at https://newsela.com. Materials that allow electricity to pass through them easily are called electrical conductors. Many metals are electrical conductors. Iron, steel, copper and aluminum are great conductors.

Objects that use electricity, like lamps, have metal conductors inside them. The metal pins used to plug a lamp into a wall socket are conductors. So are the copper wires in the electrical cord that bring the electricity from the wall to the light bulb. Inside the light bulb are tiny wire filaments. Those are conductors, too.

A common conductor is copper wire. Copper is a metal that conducts electricity well, so it's used very often. In a simple electrical circuit, copper wire connects a battery to an electrical component. The component could be a lamp or a motor, for example. When the copper wire guides the electrical current from the battery to the electrical component, it is conducting electricity. When the lamp lights up or the motor powers on, the circuit is complete.

One example of an electrical conductor that is not a metal is carbon. The graphite in pencil lead comes from carbon. All living things are carbon-based.

Water also conducts electricity. That's why things you plug in, like hair dryers and cellphones, should not be used near water. That's also why swimming pools have to close during thunderstorms.

Insulators Prevent Electric Shocks

Materials that do not allow electricity to pass through them are called electrical insulators. Plastic, rubber, wood and glass are all insulators. Air is also an insulator.

Most electrical objects are made using insulators. This makes them safe to use. Plugs have plastic cases, for example. Electrical wires are usually wrapped in flexible plastic. That prevents the wire from shocking anyone who touches it.

The copper wires used in simple electrical circuits are also coated in plastic. The plastic prevents electricity from flowing out of the circuit.

If you've ever poured a mug of hot chocolate, you know that heat is conducted in a similar way to electricity. When the mug warms up, it's conducting heat. Different types of mugs heat up more quickly than others. That's because certain materials are better at conducting heat.

Materials that allow heat to pass through them are called thermal conductors. Metals like aluminum, copper, steel and iron do this well. Many pots and pans are made out of these materials because they conduct heat. A saucepan that is made of metal allows the heat from the stove to cook the food inside it.

Coats And Socks Insulate Us From The Cold

Things that stop heat from passing through them are called thermal insulators. They can keep cold objects cold and hot objects hot. They can insulate something from the temperature outside.

This article is available at 5 reading levels at https://newsela.com. Wood, plastic and many types of fabrics are very good thermal insulators. That's why many houses are built out of wood. It's also why insulated lunch boxes are made out of plastic.

Fabrics are thermal insulators, too. A good pair of wool or cotton socks can keep your feet very warm. That's because they insulate your body from the temperature outside. Clothes, carpets and curtains are also good examples of everyday thermal insulators.

This article is available at 5 reading levels at https://newsela.com. Quiz

1 Use Image 1 and information from the article to select the TRUE statement.

(A) Glass allows electricity to easily flow through it.

(B) Glass does not allow electricity to flow through it.

(C) Glass is effective at stopping heat from passing through it.

(D) Glass is effective at letting heat pass through it easily.

2 Examine Image 2.

What does Image 2 show?

(A) an illustration of why earphones should not be used near swimming pools and other bodies of water

(B) an illustration of how plastic is a thermal insulator and copper is a thermal conductor

(C) an example of an everyday object that uses tiny wire filaments to conduct electricity and produce light

(D) an example of an everyday object that uses an electrical conductor and an electrical insulator

3 Read the following statements.

1. Materials that allow electricity or heat to pass through them easily are known as conductors. 2. Insulated lunch boxes are often made out of plastic to keep food cool. 3. Materials like steel and aluminum are used in kitchen pots and pans. 4. Insulators are materials that block the flow of electricity or heat.

Which two statements are main ideas from the article?

(A) 1 and 2

(B) 1 and 4

(C) 2 and 3

(D) 3 and 4

4 Read the paragraph from the article.

Most electrical objects are made using insulators. This makes them safe to use. Plugs have plastic cases, for example. Electrical wires are usually wrapped in flexible plastic. That prevents the wire from shocking anyone who touches it.

Which statement summarizes the paragraph?

(A) Plastic is an insulator that is used to prevent electric shock.

(B) Electrical wires can shock someone who touches them.

(C) Electrical plugs usually have plastic cases.

(D) Insulators prevent wires from getting hot or cold.

This article is available at 5 reading levels at https://newsela.com.