Insulation: Definition & Uses

Instructor: Amanda Robb
This lesson is about insulation, which you might be familiar with in your home. However, there are other uses for insulation and here we'll talk about what each of those are, as well as what can technically be considered an insulator.

What Is an Insulator?

Right now you're probably touching your computer; maybe it's on your lap. Your computer uses electricity, right? So why aren't you getting electrocuted? You might say because the plastic on the outside of the computer protects you. This is completely true, and in science we call the plastic an insulator. It keeps the electricity in your computer and outside of you!

There are other types of things insulators work on besides electricity, so we'll need to broaden our definition. An insulator is any material that prevents the passage of electricity, heat or sound from one area to another. Below, we're going to talk about how each of these types of insulators work and what they're used for in our lives.

Electrical Insulators

The first type of insulator, the one that protects you from being electrocuted, is called an electrical insulator. To understand how an electrical insulator works, we need to know a bit about electricity. Electricity is the movement of tiny charged particles, called electrons, from one place to another. Electrons move well through materials called conductors. Metals, including the wire in our power cables, are excellent conductors. Below is an image of how a conductor works.

Conductors allow electrons to flow, creating electricity

Insulators do the exact opposite. They prevent electrons from moving through them. Plastic is a great insulator, and is what makes up the coating on wires to your power charger and other devices in the house. The plastic keeps the electrons moving from the wall, through the wire, and to your computer or phone, instead of flowing out into other conductors like your body. Rubber, glass, and wood are also good examples of insulators. The white plastic on the copper wires below is an example of an electrical insulator.

Plastic insulators prevent electricity from flowing out of the copper wire
copper wire with insulator

Thermal Insulators

I don't know about you, but I love a warm home in the winter! The reason our homes stay warm is thermal insulators. Thermal insulators prevent the movement of heat from one area to another. Heat always moves from where there is more heat to where there is less heat. Below, you can see that the fire has more heat, which flows up to where there is less heat, the person's hands.

Heat flows from where there is more heat, in the fire, to where there is less heat, in the person
heat transfer

If there is more heat in your house compared to the outdoors, the heat will flow from your house to the outdoors. But this is not what we want when we heat our homes. So construction workers put special materials called thermal insulators into the walls to prevent the heat from escaping.

Fiberglass is one of the most effective and commonly used insulators in homes. Fiberglass is made of tiny fibers of glass woven together, and appears as the pink fluffy stuff you may see in the attic. It is fitted between the inside and outer walls of the house. It prevents heat from being transferred from the air inside the house to the walls on the outside of the house, and ultimately outdoors. Below is an image of house walls being constructed in a factory before being put into place. The pink filling in the walls is the fiberglass.

Fiberglass is fitted into walls to act as a thermal insulator

Plastic boards, such as those made of polystyrene, or plastic foam can also be used as insulation. For the eco-conscious home owner, there are also several types of recycled insulation, although they are not as effective as fiberglass. Mineral wool and cellulose are made from mostly recycled materials, and other natural materials such as straw and hemp are also used occasionally.

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