Last week, our oldest daughter won first place for her grade for her science fair project: Which cup will keep water cold the longest? She tested a YETI tumbler, a Tervis tumbler and a Dixie disposable paper cup.
Which cup will keep water cold the longest?
We had received some Tervis tumblers as previous Christmas presents and this year, we received two YETI cups. It seemed like they kept ice water in them longer than any cup we had used. She noticed that they were keeping ice overnight, so we started talking about different cups. Conveniently, a voluntary science fair flyer came home and she was really wanting to participate.
We talked through some ideas and helped guide her to something that could be tested (i.e. an experiment could be done) and something that we could do at home in a reasonable time.
She decided to test which of these cups would keep water cold the longest. She gathered the YETI tumbler, a Tervis tumbler and a Dixie disposable paper cup all with their respective lids, a thermometer (that I borrowed from our local high school science department), a timer (we used a phone), a pitcher (to start with the same water), some ice, a measuring cup and funnel.
She wrote her hypothesis: The YETI will keep water cold the longest.
We created the ice water in the pitcher and tired it around and allowed the ice to melt (so we started with ice cold water all at the same temperature). Then, measured out the same amount of water into each of the cups.
She took the temperature in each cup (just in case it varied right away) right at the start, and then collected the temperature at various time intervals.
We also got to have a fun lesson in reading an analog thermometer and estimating to one decimal place. She decided on the intervals in which she would take the temperature of each water and was in charge of setting the timer, being at the water when the timer went off as well as taking and recording the temperature on her data chart (see the picture above).
I know you are here to see the data. Well, here you go. (I should start by adding that room temperature in our house during most of this was around 20 degrees Celsius). After 6 hours, the YETI was still significantly colder than room temperature or the other cups. Remember, this started off as water. There wasn’t any ice in the cup. If there were, I think the water would have stayed cold longer, but it would have been much harder to measure and harder to control all of the variables and temperature readings.
After 20 hours (we had to do a long gap overnight because she was sleeping), the YETI was still slightly cooler than the DIXIE and Tervis tumblers were at about 2-3 hours. I think the results at 20 hours are a little off because our house cooled down overnight (why they didn’t stay at the higher temperature).
Looking at the initial slope of each of the lines for each of the cups, you can see that the Tervis Tumbler and the Dixie cups both allowed the water to warm up much faster than the YETI tumbler.
The YETI tumbler keeps water cold the longest. Now, take that as you will. Some people might drink their ice cold water and not care that it will still be cold 6 hours later. Others might drink their ice water fast and not care. For me, if I’m exercising, it will be gone quickly. If I’m just hanging out, I end up sipping on it. Now, if you are talking about maybe a mixed adult beverage, that’s something you might want to stay cold a little longer.
While we haven’t tested the cups with hot water, I’m going to predict that the cups would cool off at the same rate and that the YETI would keep water (or a hot beverage) hot the longest.
The Take Home Message
The YETI tumbler will keep your water or cold beverage cold the longest compared to a Tervis tumbler or a Dixie disposable paper cup. While they are pricier, it seems that they are better at insulating beverages, so you get what you pay for.
On More Experiments
I fully acknowledge that there are many other types of insulated cups out there on the market. We used cups that we had and tried to keep it to a reasonable experiment for a third grader. I do think it would be fun to compare other cups at a later date. And, doing that, I would probably head back to the local high school science teacher friend and ask them for a probe that collects the temperature at set intervals and records them. Of course, that would be for my own curiosity and not for helping the third grader with her science experiment.
On the Science Fair
I intentionally didn’t present all of the information from our daughter’s project so that it will have to be done again if somebody wants to present it as their own. I think it’s important to make sure you follow the guidelines for your science fair and include all of the necessary parts requested (research, materials, procedure, etc). It’s also important that the person doing the experiment and being judged / graded for it is the one that puts their project and presentation together. If you do have a question, feel free to reach out emailing me or using the contact form and I will try to help. But, being a “retired” science teacher, I’m definitely not one to give out all of the answers!
Are you surprised by these results? Or is it pretty much what you expected?
(This isn’t sponsored by anybody. Everything that we used was borrowed, gifted for Christmas from family or something we bought. There are affiliate links. If you buy something using them, it won’t cost you anything. And, if enough people buy a YETI tumbler, in about a year, we’ll have enough to grow our collection!)