Monday, March 1, 2010

Ice Cream Cooler

Hey there, Mad Scientists! Here is an at-home experiment you might really enjoy! To make ice cream "feel colder" while you eat it, you will need: 2 bowls, ice cream, milk, a spoon. Put a couple of spoons of ice cream into each bowl. Taste a bite of ice cream from the first bowl. Notice how it feels, as well as how it tastes. Yes, I know that it is cold, but pay attention to how cold. Pour a couple of spoons of milk over the ice cream in the second bowl. Take a spoon of this ice cream, making sure that the surface of the ice cream has a coating of milk. As you eat this spoonful, again notice the temperature. It should feel colder. Just to be sure you notice the difference, alternate bites between the regular ice cream and the ice cream with milk until you are sure of the difference. This may take several bowls of ice cream.

Now think about this: Why would adding milk make the ice cream seem colder? It has to do with the transfer of heat. The ice cream feels cold because it has less heat than your mouth does. As heat moves from your mouth to the ice cream, you feel the cold. The faster the heat moves away from your mouth, the colder the ice cream feels.

Why would adding milk let the heat move faster? To see that, put a spoon of ice cream in a bowl and let it melt. I know that it may seem like a waste of good ice cream, but it is necessary. You can also use a very small spoonful, as we only need a little. Compare the melted ice cream with the milk.

What is the difference? The ice cream is much thicker. This thick mixture contains many tiny bubbles. These bubbles give ice cream its pleasing texture, but they also act as insulation, just like the tiny bubbles in Styrofoam and many other types of insulation. The milk does not have the bubbles and so it makes a much better pathway for the heat. The coating of milk on the ice cream carries the heat quickly from your mouth to the ice cream and you get a colder sensation.

Pretty neat! Leave a comment if you try this to let the class know your thoughts.