psocoptera (![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png)
psocoptera) wrote2014-01-14 02:35 pm
psocoptera) wrote2014-01-14 02:35 pm
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science for tinies and tiniers: sink and float yet again
We read What Floats In A Moat by Lynne Berry in which Archimedes the Goat experiments with making boats from full, empty, and half-full barrels. Obviously we had to try it ourselves. I filled the sink with water - I've always been weirdly reluctant to do this because it's so much more water than a bucket, but it's absolutely worth it for the kids not being able to spill it, plus we could get it nice and deep. We didn't have a barrel so we used an old plastic jar. I taped a piece of styrofoam on one end to (hopefully) reduce spin, in mimicry of the barrel ships from the book.
In the book, the full barrel sank, the empty barrel bobbed on the surface of the water and rolled the goat off, and the half-full barrel sank partway and floated and was stable.
Our "full" jar turned out to have a substantial air bubble in it, so it didn't quite sink, but it mostly sank. Our empty jar did indeed bob and roll nicely. Our half-full jar also rolled quite a bit, it wanted to float on a diagonal with the fin-end out of the water.
We were having fun floating things, so I made a little canoe out of a piece of aluminum foil. Which floated. But I didn't make it very well, so it started to fill with water and sink! I re-made it and it floated very nicely. Then I tried folding it flat (as per rose_garden's suggestion) and I guessed that it would sink and Junie guessed that it would float and... it still floated. I tried refolding it but I could not get it to sink.
We failed to actually talk much about any of this or use the word "displacement", science took a backseat to stopping Q from chucking other things out of the drying rack into the sink.
I think next time I'm going to challenge Junie to try to make a foil boat that can hold a small toy and see if we can do it, she really liked the foil canoe thing.
In the book, the full barrel sank, the empty barrel bobbed on the surface of the water and rolled the goat off, and the half-full barrel sank partway and floated and was stable.
Our "full" jar turned out to have a substantial air bubble in it, so it didn't quite sink, but it mostly sank. Our empty jar did indeed bob and roll nicely. Our half-full jar also rolled quite a bit, it wanted to float on a diagonal with the fin-end out of the water.
We were having fun floating things, so I made a little canoe out of a piece of aluminum foil. Which floated. But I didn't make it very well, so it started to fill with water and sink! I re-made it and it floated very nicely. Then I tried folding it flat (as per rose_garden's suggestion) and I guessed that it would sink and Junie guessed that it would float and... it still floated. I tried refolding it but I could not get it to sink.
We failed to actually talk much about any of this or use the word "displacement", science took a backseat to stopping Q from chucking other things out of the drying rack into the sink.
I think next time I'm going to challenge Junie to try to make a foil boat that can hold a small toy and see if we can do it, she really liked the foil canoe thing.
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