This post contains affiliate links. I was compensated for my work in writing this post.
Today we are doing a “Freezing Alcohol” experiment where we will put different amounts of alcohol combined with water in the freezer to see which will freeze first. My younger two children are using Christian Kids Explore Chemistry by Bright Ideas Press, and this is one of the experiments in the book.
Grab three plastic containers with lids. You need lids because alcohol evaporates so easily, and we don’t want the alcohol to evaporate out of the containers and affect our results.
Label the three containers by writing on paper with a black permanent marker. Attach the labels with packing tape. Here are the three labels:
- Water only
- 70% Isopropyl Alcohol
- Water + 70% Isopropyl Alcohol
The water only container is the control. We will see how fast normal water freezes and compare that to the amount of time it takes for alcohol to freeze, if it freezes at all.
Grab your rubbing alcohol from your medicine cabinet. This alcohol will say “70% Isopropyl Alcohol.” Pour the alcohol into the second container.
The third container should have half alcohol and half water. If you put 100 ml of water in the first container and 100 ml of alcohol into the second container, you will want to put 50 ml of water and 50 ml of alcohol into the third container.
Place all three containers into the freezer and wait two hours. Then pull them out and remove the lids to see what is going on. The first container was frozen solid. The second container was sort of frozen on the bottom, but liquid on the top. The third container was completely liquid with no ice whatsoever.
Even after 24 hours, we have similar results, except for the second container. Take a look:
Alcohol definitely has a lower freezing point than water does. In fact, a normal household freezer (which is around 0 degrees) will never be able to freeze the alcohol unless the temperature of the freezer is lowered considerably! Of course, you would not want to do that to your freezer, or all your food would get freezer burn!
Tags: Bright Ideas Press, chemistry, Christian Kids Explore Chemistry, experiment, hands-on science, Homeschooling, science
great experiment! It’s always so surprising to me that alcohol doesn’t freeze like water. I have used a little in sorbet recipes to keep it soft! <3
That’s a good idea to use it in sorbet!
Freezer burn happens when the food is alternately thawed and refrozen. This happens in “frost free” freezers. It’s not due to a lower temperature. In fact, “deep freeze” freezers, used for longer term food storage, are kept at a significantly lower temperature than the freezer in your fridge. The food is not freezer burned because the they are not “frost free”, or self-defrosting.
Also, if my freezer had been substantially colder, I could have frozen the alcohol!
One of my favorite things about your science experiment posts (aside from the great content) is the lab coats. When you’re serious about science, dress the part! 🙂
I love the lab coats, too! They were super inexpensive at Goodwill.
I’ll have to do this with my boys. They love science experiments.
Experiments are the best way to teach science!
I love the lab coats. What a cool experiment!
It was definitely cool, since we used the freezer!
Great experiment.
I would like to freeze (or separate water from 70% alcohol).
Can I scientifically do this in a freezer? Help please, I am stumped!
Other options like salt or distilling look too complicated for me.
Thank you.
You could search on YouTube what you are trying to accomplish and see if someone else has done the experiment you want to perform.