What is the Role of a Conductor?

You may be more acquainted with conductors than you realize. If you have ever used a tea cup, worn an oven mitt, or taken a sip from a thermos, you have firsthand experience with thermal conductors.

Heat has a tendency to move, but only in one direction. Did you know that heat only travels from warmer objects to colder objects? This becomes clear when you understand that there is no such thing as “cold.” There is only heat. Cold is simply the absence of heat!

If you hold an ice cube in your hand, it may appear that the coldness of the ice cube is making your hand cold. However, the truth is that your hand is actually warming up the ice cube, as heat travels from your warm body to the cold ice.

The result? A melting cube. As your hand loses heat to the ice cube, it feels cooler.

Some materials easily transfer energy, such as heat. These materials are known as conductors. Metals are excellent conductors because energy passes through them quickly.

On the other hand, there are materials called “insulators” that do not allow energy to pass through easily. These materials include plastic, cork, wood, Styrofoam, and rubber. Thermal insulators are effective at maintaining a consistent level of heat — whether hot or cold.

A thermos is a great example of a superior insulator. If you pour soup into a thermos, you can open it later and enjoy warm soup on a cold winter day. The thermos insulates the soup, keeping the heat inside.

Similarly, if you are playing soccer on a hot August afternoon, your thermos full of ice water stays refreshing and cold. The thermos acts as an insulator, preventing heat from entering.

As you may have already guessed, insulators are not good conductors. Manufacturers utilize this scientific fact to create safer products.

Take the teapot, for instance. If you have ever examined a teapot closely, you may have noticed that the body of the teapot is made of metal, while the handle is made of wood or plastic.

The body of the teapot must be able to conduct heat in order for the water inside to boil. Since metal is an excellent conductor, it easily transfers heat from the stove to the water inside. This is why manufacturers use metal for the body of the teapot.

You already know that it would be a very bad idea to touch the body of the teapot with your bare hand. Fortunately, it has a handle. However, if the teapot handle was made of metal, it would also transfer heat from the stove to your hand, resulting in an unpleasant surprise.

To prevent burns, manufacturers make handles out of good insulators, such as wood and plastic. This allows you to enjoy a warm drink without burning your hand.

Give It a Try

Are you ready to heat things up or cool things down? Ask a few friends or family members to assist you in exploring the following activities:

  • Are you prepared to conduct some experimentation at home? Go to the kitchen, which will serve as your laboratory for today. Make sure to seek assistance from an adult friend or family member, as this experiment involves hot water. Fill a bowl with hot water (it doesn’t have to be boiling). Attempt to submerge various objects in the water to determine their thermal conductivity. For instance, you can compare the following items: a metal spoon, a plastic fork, and a pencil. Objects that are good thermal conductors will transfer heat from the water through the object to your hand, and you will feel the heat shortly after submerging the object. You will not notice any difference when submerging items that are poor thermal conductors. Enjoy your experimentation!
  • You have already discovered that metals are efficient conductors of heat, but which metal is the most efficient heat conductor? Go online and follow the instructions for this fascinating experiment on the Thermal Conductivity of Metals. Share your findings with a friend or family member.
  • Do you want to educate a friend about what you have learned about thermal conductors? Find a couple of thermoses and plan a picnic. Heat up your favorite soup and place it in one of the thermoses. Fill the other thermos with your favorite cold beverage. Head to your preferred picnic spot and teach your friend about thermal conductivity by explaining why the thermos can keep your soup warm while also keeping your drink cold!

Sources of Wonder

  • http://www.physics4kids.com/files/thermo_transfer.html
  • http://www.lovemyscience.com/heatconductorsandinsulators.html

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