Science Buddies: "Ask an Expert"

Hello,

My daughter is in 3rd grade and this is her first science fair. She has decided to do an experiment where she will test to see which of three liquids will freeze first. The three liquids she has decided to test are water, vinegar, and fruit juice. She has already turned in her question to her teacher and is preparing to turn in her proposed methodology this week. However, her teacher asked her a very interesting question that we couldn't answer. The question was how will we benefit from the answer. We haven't answered that yet and any suggestions would be great.

While I have you, I'll also ask if anyone has any suggestions on things to think about as we pull our method together. We'll probably use styrofoam cups to hold the liquids, toothpicks to check for freezing, and a thermometer to ensure the same starting temp before the test. We'll probably check at 10 minute intervals until we establish a freezing point for each liquid. For the second and third round, we'll probably spread the intervals out to about 20 minutes. Finally, we'll do a final round only opening at the times we've identified as the freezing point for each. Hopefully, this will allow us to determine a more accurate freezing time for each without the constant opening of the freezer door.

Any help you can give us is greatly appreciated. This is a very helpful site and I wish I would have stumbled across it sooner. My daughter really wanted to do something that involved the sun and I'm sure this site could have helped us figure out a good project.

Thank you in advance!

Hi,

I hope your daughter is enjoying her first science fair project! I think it sounds like you have chosen a fantastic project. Has she formulated her hypothesis or prediction as to which liquid will freeze first and why? You may want to spend some time with your daughter investigating what happens to a liquid and why at the melting/freezing point (i.e. molecules and what changes about them). Both of your liquids contain some amounts of water so essentially you are testing pure water, and water with various other molecules added to them which will determine how long those molecules will take to rearrange themselves into a honeycomb like pattern upon freezing. Another possibility would be to add another liquid which would be water with salt. This would provide a very clear benefit of the experiement that we are all familiar with - antifreeze. We wouldn't see to many cars out on the road during the winter months in the cold weather climates without it. Of course, the experiment sounds great as it is. The benefit being that if we set our fridge temp too cold we may be pouring ourselves a block of orange ice instead of a perfectly cooled drink of o.j. Actually there are countless benefits to knowing the freezing temperatures of liquids some of which I mentioned but also in cooking, storage, and transportation, and from personal experience medication. Our family stayed at a hotel once and we had some medication that needed to be kept refridgerated - no problem we had a mini fridge. Unfortunately, when we took it out it was frozen. We called the pharmacy who in turn had to call the manufacturer. The verdict? It was no longer effective once it reacheck the freezing point. The supply list looks good just keep everything consisitent from the clock that you use, exact measurement of liquids, and exact recording times. Best of luck. I did want to mention that we do have a link on Science Buddies you may want to take a look at just for some background information on how a similar experiment was conducted. Here is the link: https://www.sciencebuddies.org/science- ... p023.shtml

Thank you so much for the feedback! I will check out the page you suggested and get to work helping her pull together the foundation for her hypothesis.