Density and Floating: Would King Lear Sink or Float in Lava?

Boop Tackles Shakespeare. You Can Too!

Hi! It’s me, Boop! I’m the Discovery World spokesturtle. We hope you continue to be well. It sure feels like Friday (hooray?), but it’s kind of hard to tell. Maybe it’s Thursday. No. This definitely feels like Friday. It’s Friday! I just know it.

It’s still April, I think, and there are signs of spring everywhere. I’ve seen some of them with my own eyes! The grass is growing again. I saw a bug the other day. Then I ate it. Daffodils are popping up. Robins are flittering about and rabbits are hopping around. So that’s something. When you can, get outside and look for signs of spring. How many can you find? What’s your favorite sign of spring?

Good news! You know how Shakespeare wrote King Lear while he was in quarantine? Guess what? I did, too! It was easy! It only took me a week. It’s a little shorter than the first one because I didn’t always understand what was going on. So I skipped a bunch of stuff (so much talking!). Also, my hand cramped up a lot. It’s more of a claw than a hand, but there was still cramping.

And I made some changes. Gloucester is a now a turtle. So are Cordelia and the Fool. King Lear is a red-eared slider. That’s a kind of turtle. Everyone else in the play is either a fish or a frog. Edmund is a poisonous dart frog. And everyone exits pursued by a bear. They also enter pursued by a bear. There’s a lot of running from bears.

Oh! And I fixed the ending. Instead of dying of a broken heart or whatever, a volcano erupts on stage, and Lear throws himself into it. That seemed more dramatic and fun. What I couldn’t figure out is if King Lear would be able to deliver his final lines from inside the volcano. What I mean is, would King Lear sink or float in lava?

SCIENCE TIME!

Okay, let’s say that you’re about to leap into an active volcano. It’s a really active volcano, like it runs half-marathons and it’s super into CrossFit and yoga and everything.

Now, I don’t know why you’re leaping into an active volcano. Maybe you’re trapped in a Tom Hanks and Meg Ryan movie. Not Sleepless in Seattle, the other one. The other other one. The one with the volcano. Or maybe you’re playing the lead in Boop’s King Lear.

Anyway, you’ve made the leap. You’re plummeting through the air having all kinds of second and third thoughts. One question that no one was quite able to answer before you agreed to leap into the volcano was, “Will I sink or float?”

That depends on whether you are denser or less dense than lava.

Density is property of matter. It’s the amount of stuff in a given amount of space or mass per unit of volume. Density is measured in kilograms per cubic meter. It can be measured other ways, including grams per cubic centimeter and slugs per cubic foot. A slug here is a unit of mass not the slimy, terrestrial, gastropod mollusk (yum!).

A cubic foot of slugs would be super delicious. Better than mealworms, even! Actually, I don’t know if I’ve ever eaten a slug. You’d think I’d remember something like that. They sound good.

A cubic meter of air has a mass of 1.3 kilograms. A cubic meter of fresh water has a mass of 1,000 kilograms. So air floats on water, but you knew that already.

A cubic meter of ice has a mass of 917 kilograms. That’s why ice floats in water! Water is one of a few substances that are denser as a liquid than a solid. Water is weird. It’s awesome, but it’s weird.

Anyway, a cubic meter of people has a mass of 985 kilograms. A cubic meter of steel has a mass of 7,700 kilograms. Human beings float in water. Steel does not.

Hang on, you might say. Big ships are made of steel, and they float in water. True! But ships hold air. Most of the ship is air, so the overall density of the ship is less than water. A raft made of solid steel would be less successful as a means of aquatic conveyance.

FUN FACT! Turtles don’t float because our shells are denser than water.

But will you or a turtle or King Lear or Turtle King Lear float in lava? Lava, which is molten rock, has a density of around 3,100 kilograms per cubic meter. It’s over three times denser than water. You are slightly less dense than water. I am slightly denser than water. So, yes. You would float in lava. So would I. Don’t try this at home. Not that you could try this at home. I mean, I assume you don’t have an active volcano at home.

ANOTHER FUN FACT! If Lake Michigan were filled with mercury instead of water, a cubic meter of lava would float on it. Mercury (the metallic element, not the planet) has a density of 13,593 kilograms per cubic meter. Mercury is much denser than lava. Mercury the planet has a density of 5,420 kilograms per cubic meter, so Mercury would float in mercury. You’d need a much bigger, much deeper lake of mercury, though.

YET ANOTHER FUN FACT! Would the planet Saturn float in water? No. Saturn is less dense than water, yes, but there’s a different problem. Let’s say you were somehow able to place Saturn onto a ginormous planet covered entirely with water. This would be a massive planet about the size of a small sun. Okay, great. Saturn is made of gas, mostly hydrogen with some helium, methane, and a few other gasses. But Saturn also has a molten core made of rock.

The gravitational field of your hypothetical ginormous water planet is going to be much, much stronger than the gravitational field of Saturn. The hydrogen and helium would stay at the surface of your water planet while the rocky core would sink to the bottom. So some of Saturn would float, some would not. And after this experiment, Saturn wouldn’t really be a planet anymore.

ONE MORE FUN FACT! WELL, TWO, BUT THESE FACTS ARE SO FUN WE’RE NOT STOPPING TO COUNT THEM!

The densest naturally occurring element is Osmium at roughly 22,500 kilograms per cubic meter. Neutronium (the stuff that neutron stars are made of) has a density of 1 quintillion kilograms per cubic meter. Grab a measuring teaspoon. Fill it with flour or sugar or sand or something. Now pretend that that teaspoon of stuff weighs 10 million tons. That’s how dense neutron star stuff is.

So that’s density in a nutshell. Or a volcano. Or something.

Anyway, the aquarists have promised me that we’ll stage a production of Boop’s King Lear next week! Beep and I are building the volcano now! It’s not a real volcano. Those are dangerous. And I have to teach fish how to talk and read and act. That should be fun. And after that I’m going to write Hamilton!

Be well,

Boop!

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Getting Here

We are located on Milwaukee’s lakefront with easy access on and off of the expressway.

500 N Harbor Dr
Milwaukee, WI 53202
Get Directions
Adults $20
Child (3-17) $16
Child 2 & Under $Free
Senior (60+) $16
College Student* $14
Military Active and Veterans* $14
Military* Active Duty & Veterans $14

*Valid ID Required.

Purchase tickets at Admissions. Prices are subject to change.

Hours

CLOSED
Tues-Fri CLOSED -
Sat & Sun CLOSED -