Archimedes Water Displacement Science Lesson

We’ve learned how to find the volume of a cubical object (such as my son’s bedroom). But how does one find the volume of something as odd-shaped as a rock? Using Archimedes’ story as an example, we made our own kitchen Archimedes water displacement science experiment to understand the concepts and reach our own “Eureka” moment.

Archimedes and Water Displacement Stories

As I hope is evident by my interest in providing my kids with engaging picture book lessons, I love it when reading time intersects with simple learning lessons, activities, crafts, and so forth. Learning about the Greek scientist and mathematician Archimedes was a perfect segue into a kitchen table science lesson.

Archimedes and the Golden Crown, an audiobook story written and narrated by Jim Weiss, is a retelling of the traditional story of Archimedes determining how to figure out the volume of an awkwardly shaped object. Although there is no direct proof of the story of Archimedes running through the streets naked yelling, “Eureka!”, Jim Weiss’ master storytelling abilities give the concept of water displacement a memorable context. He treats the story as true, and the tale of golden crowns, lying jewlers, and a naked mathematician make it funny for the kids to listen to. If you are not familiar, the story goes that

Mr. Archimedes’ Bath by Pam Allen does not even try to be factual, but that is okay because the silly man taking a bath with his kangaroo, goat, wombat, etc., is amusing enough. In this story, Archimedes wonders why the tub keeps overflowing. He finally comes to the conclusion that he and all the animals have displaced the water from the full tube, and therefore.

What Floats in a Moat? by Lynne Berry and Matthew Cordell features a goat named Archie (after Archimedes). In his silly scientific experiment, he is trying to see what will float in a moat, with three iteratios: a barrel of buttermilk (full), an empty barrel, and a barrel half full of buttermilk (because his trusty sidekick could not drink it all). Of course, it is the half-full barrel that provides enough ballast to balance in the water just fine, thus teaching why boats needs to have some weight in order to be seaworthy. It was alesson that was lost on my littlest one, but prompted more discussions (and ideas for more experiments) for my older one!

Water Displacement Science Lab for the Kitchen Table

If you are not familar with the traditional “Golden Crown” story, I’ll summarize it as so: Archimedes needed a way to show the king that the golden crown he was given was actually not solid gold. Since he knew that silver weighed less than gold, it would take more silver to bring the golden crown to the proper weight. Archimedes struggled to think of a way to determine the proper volume, and eventually came to realization while he was in the bath (supposedly).

We did not have a way to measure quite such a large volume of an item. And I certainly did not have seven pounds of gold. So we obviously adjusted the scale of our lab to fit in our kitchen. I found the perfect tool for measuring right in our kitchen cupboard: my small liquid measuring glasses.

Do you use small liquid measuring cups? I received one of these for Christmas a few years ago, and I’m surprised how often I use such a small volume liquid measure. Measuring oil, medicine (for the kids), bits of water for recipes. Because these cups provide Tablespoons, ounces, and milileter measuring lines, I feel I have plenty of choices.

Anyway, for this task, my small liquid measuring cups were perfect because they had enough lines to show small increments of change.

In the story about Archimedes, he filled his bowl to the top and then measured the spillover for both the crown and the 7 pounds of gold. We found that measuring the spillover was much harder than simply measuring the before and after of the two rocks. We supposed that Archimedes did not have equal glass beakers with which to measure the change, so we decided to document the difference in water level once the rocks were added to the glass beakers.

So, first we put 100ml of water into the glass beakers.

When we were sure they were equal, we added the rocks. We could then compare what the new levels of the water were. Raisin was surprised that the left rock (the brown one) was just over 120ml while the other was at 135ml. We had thought the brown one looked larger.

Now we know! What a fun, but simple, way to make an historical story come to life!

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Storybook Science in the Kitchen

For the next month, my fellow bloggers will be sharing storybook science ideas! This week, we’re focusing on “In the Kitchen” science. Click the image below to see the other posts.