Heat naturally flows from a hot area to a cold one. This means that if you pour a hot drink into a cup, it will soon cool down to the same temperature as the cooler air around it. However, materials that are good insulators can help slow down heat loss -- or prevent warmer air from getting into a fridge or cooler. Several everyday materials are better insulators than other materials. Simple science experiments can help students identify and investigate different insulators.
Everyday Objects with Insulation
In this science project students observe and examine everyday objects around them. Ask students to write down what the handles on objects that heat up, or items that allow you to safely touch hot objects, are made from. These household items may include frying pans, electric kettles and pot-holders. Students will find that most of these items are made from wood, plastic, rubber or thick cotton. Explain that these items are designed this way because these materials are poor conductors of heat, and therefore good insulators. This means that they will not transfer heat and burn your hand when you use them correctly.
Plastic and Wood As Insulators
A good insulating material is a poor thermal conductor. This means that it does not transfer heat from a hot area to a cold area well. Use a simple demonstration to illustrate good insulators such as wood and plastic. Pour hot water into three identical cups or beakers. Place a plastic straw in one cup, a wooden chopstick in the second and a long-handled metal spoon in the third. Wait five minutes and then ask the students to carefully touch the end of each of the items. The students will feel that the plastic straw and wooden chopstick are cool to the touch, while the metal spoon is not. Explain that this demonstrates that wood and plastic are good insulators, while metal is a poor insulator because it is a good conductor of heat.
Will a Foam Cooler Keep Drinks Colder?
Portable picnic coolers for cold drinks are often made of foam or plastic paneling that is insulated with foam because this material does not conduct heat well. Foam drinking cups keep cold drinks cold and hot drinks hot, due to the same properties. Students can use a small picnic cooler in a simple experiment to determine if foam is a good insulating material. Refrigerate bottled or canned cold drinks of the same variety and size until they are cold. Place a few drinks in the cooler and an equal number of drinks in a cardboard box of the same size, and leave both the foam cooler and the box in the same room. Wait a few hours and check the temperature of the beverages with a thermometer. As foam is a better insulator than cardboard, the drinks from the foam cooler will be colder.
Is Air a Good Insulator?
An easy science experiment can compare the insulation qualities of air with various other materials. Students will need to place ice cubes in four identical glass jars with tightly fitting lids. Insulate one jar with air-filled bubble wrap, another with newspapers, the third with plastic and the last one with aluminum foil. Place all the jars outside in the sun and wait 15 minutes before checking to see which insulator has best protected the ice cubes from the heat of the sun. As air is a better insulator than the other materials, the jar wrapped in bubble wrap should have the least melted ice cubes.
June Kane is a Registered Radiation Therapist (RTT) and radiotherapy instructor from Manitoba, Canada. Her writing experience includes peer-reviewed articles in the Lancet and Journal of Nuclear Medicine and Radiation Therapy, patient information booklets and website content, and student curriculums.