Freezing Experiments

2013-02-06 06:38:19.000 – Michael Kyle,  Summit Intern

As some of you might have seen on the Mount Washington Observatory Facebook page last night, the observers took advantage of the cold temperatures to display the properties of Charles’ Law by use of balloons. In the past, the observers have used experiments in the extreme cold to show how boiling water crystallizes when thrown into the air and how a soapy solution can be used to make bubbles that freeze before sinking to the ground. While you might not see the extreme cold as we do here on the summit, you can still enjoy the science of cold air. Here is a simple experiment that you can do right from you own home.

This experiment demonstrates the freezing points of different liquid solutions. To run this experiment all you need to do is partly fill three containers; one with regular drinking water, one with a saline solution (salt water), and one with Soda. If possible place a thermometer in each container. If you only have a thermometer that measures air temperature that just place it near the three containers. Then place the three containers and thermometers outside. Ideally you want to put the containers out when the temperature is warmer than 32F and dropping. If that scenario is not possible then just place the containers outside when temperatures are 32F or colder.

When the containers have been outside for at least 30 minutes go out and check if any of them have begun to freeze. If they have begin to periodically, every 15 to 20 minutes, check the containers temperature. For colder temperatures you may want to check more periodically. When observing the containers monitor at what temperature each one begins to freeze at. This will, in the end show you the different freezing points of different solutions.

These are the results you should get:

Solution / Temperature Range:
Water / 32F or less
Saline Solution / 27F to 29F or less
Soda / 20F to 15F or less

**Please note that temperature ranges for the saline solution and soda may vary depending on the amount of salt and sugar in each one respectively. The more salt or sugar the colder the temperature required for them to freeze.

These are just three suggested solutions to try. It is encouraged to try whatever you have around your house. Some other ideas are orange juice, pudding, or chocolate/maple syrup. Just be mindful that some solutions will require temperatures below zero to freeze.

Good Luck, have fun, and stay warm.

Michael Kyle,  Summit Intern