EXPERIMENT 1:

HOW DOES INSULATION WORK?

THINGS YOU NEED: A small water glass. Inexpensive “fish tank” thermometer. A cardboard box (find one made out of corrugated cardboard; it should be just big enough to hold the water glass). A handful of cotton balls (you can buy these at any drug store).

During the winter, the insulation in your home’s walls slows down the movement of heat from inside to the cold outdoors. To understand how insulation works, you must first study how quickly heat will flow from a warm object to cold air when no insulation is present.

Fill the glass with water that is at room temperature (about 70°F); use your thermometer to measure the exact temperature. Put the thermometer into the glass, then place the glass inside your refrigerator. Check the water temperature every five minutes.

You will find that the water temperature drops quickly. ..probably three or four degrees every five minutes.

The reason, of course, is that heat is flowing out of the relatively warm mass of water and into the relatively cold surrounding air inside the refrigerator.

Now, let’s add some insulation. Here’s how: First, refill the glass with water at room temperature. Then, place a layer of cotton balls inside the bottom of the cardboard box, and rest the glass atop the layer of cotton. Finally, pack the empty space between the glass and the sides of the box with cotton balls. Now repeat what you did above. You’ll find that the temperature will drop much less quickly, now. . .maybe only a degree or so every five minutes. The cotton insulation is slowing down the loss of heat from the mass of water in the glass.