Rene Descartes (1596-1650) was a French scientist and mathematician who used this same experiment show people about buoyancy. By squeezing the bottle, the test tube (diver) sinks and when released, the test tube surfaces. You can add hooks, rocks, and more to your set up to make this into a buoyancy game!
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Not really, because the cap needs to be screwed on tightly (so it won’t pop off when you squeeze the sides) and you also need the container to be clear so you can see through it.
Would a plastic milk container work in place of a 2 liter bottle?
No – you can use a plastic tube or even a medicine dropper. It just needs to be neutrally buoyant and then you make it slightly positive.
In this experiment, does this need a glass test tube?. We are using a small plastic one and you have to fill it mostly with water and when you squeeze the bottle, it stays put.
Yes the ones from C1000 are a little large. You can order smaller ones inexpensively here, or use a disposable medicine dropper.
Our test tubes don’t fit inside the opening of a 2-liter bottle. They ALMOST do, but don’t. I think my test tubes are a standard size (came in Chem 1000); are there brands of soda that have bigger openings? We had Coke and A&W Root Beer bottles.
Did it settle near the top or the bottom when you tried this experiment?
We had hard time with this experiment. We tried numerous times. The test tube would not stay straight and didn’t move when we squeezed the bottle. Any ideas?????
Kids had a great time watching the videos and performing this experiment. We marked our test tube each time we added water. It gave them a great point of reference for adding more/less water. They just raced downstairs to write in their science notebooks – Thanks Aurora!!
These labs are part of the summer e-Camp program, which is available June through August. They are fun, aren’t they?
Are these labs open to us during the winter if we’re an e-science member? I asked this question before, but got on too late to see the answer.
I loved that video!
Sounds like it’s not heavy enough – what kind of weight can you add to it?
even when we fill our testtube full of water it will not go far enough down do we need a glass testtube
Glad you figured something out! Remember, this is also a great lesson in flexibility with your kids – it often doesn’t matter HOW you get the result you were after as long as you get the outcome! 🙂 Being “married to the procedure”, which means feeling like you have to do the same exact steps you think you should take is one of the biggest mistakes students make.
We had difficulty making the test tube work. In fact, I filled the test tube completely with water and it wouldn’t sink. So we tried a ketchup packet and the experiment was more successful. It was a fun experiment.
Thank you,it works and it is totally awsome !!!!!!
This one takes patience… 🙂 Adjust the level in your diver one drop at a time and you’ll find the perfect balance. Take your time…
I can’t find the right amount of water HELP!!!