# Transcript: Density and Buoyancy: Testing Liquids

(electricity crackling)

RACHEL: Do you think a grape would sink or float in corn syrup? How about water or oil? Well, Paul H. of Eagan, Minnesota wants us to find out.

See, this is corn syrup and it's clear. This is water, and it's blue because we put food coloring in it.

This is oil, and it's yellow.

KALEIGH: Here we go— Okay— so, this is corn syrup. And here comes the water. Oh, that's cool. Almost there?

ZOOMer: The color is really neat.

RACHEL: Awesome. And now for the oil. And... It's so cool. Mm-hmm.

KALEIGH: Density is one of the things that makes things float. These three liquids can float on top of each other because they have different densities.

The most dense is the corn syrup the least dense is the oil, and the density of the water is in between the corn syrup and the oil. Since the oil is the least dense it's able to float on top of everything.

We're going to drop these grapes and see in which liquid it floats and in which liquid it sinks. Drop one in the syrup. (gasps) It floats.

RACHEL: Oh, my goodness.

KALEIGH: Okay, so, let's see if it floats in the water. Here we go. Oh, it sinks. Ready? Oh. It sinks.

If we were right, the grape should fall through the oil and the water and float on top of the corn syrup. So, here. Let's drop it in. Awesome! That's so cool. Look at that.

RACHEL: That's cool, you see, like, bubbles inside, too.

KALEIGH: Yeah— now, we have some plastic building blocks some metal nuts and some styrofoam.

So, which liquids do you think they'll float in?

RACHEL: Um, well, first let me check the weight for... for, like... I think... whoa, this is much heavier than the grape. Oh, yeah. So I would think this one would just sink straight down right through. but I think the plastic building block is less dense than the grape. I think it might float between the water and the oil.

KALEIGH: Here, let's do the metal nut. Ready?

Oh, right to the bottom. Yep, you were right— nice job. Let's drop it in. Let go. Uh-oh, hold on. Let me get those air bubbles out. So, I'll push it down a little. There we go.

RACHEL: Oh, we were right.

KALEIGH: Cool.

RACHEL: It's between the water and the oil.

KALEIGH: Let's see what happens when we push the grape down. Here, I'll reach all the way down there.

RACHEL: (chuckling)

KALEIGH: Oh, it just floats back up.

RACHEL: Oh, that's awesome.

KALEIGH: Yeah, that's pretty neat. I need to wipe my hands. Thank you. Okay. So, want to try the styrofoam?

RACHEL: Yeah.

KALEIGH: Okay, do you want to drop it in? Yep, go ahead. Yeah, push that one down, too. I don't think that one wants to go down. Yeah, I think that one definitely floats on top of the oil.

RACHEL: Oh, that's gross.

BOTH: (both laughing)

KALEIGH: That's really neat.

RACHEL: That's awesome. It's so cool to look at.

KALEIGH: There's one on each level. Yeah. So, the Styrofoam's on top. Then the building block... and the grape... and the nut.

BOTH: Cool.

KALEIGH: The corn syrup is the most dense, the oil is the least dense, and the water is in between the corn syrup and the oil. So, if you're still wondering what density is here you go. See that these three liquids take up the same amount of space in their containers.

But the denser one, the corn syrup, is heavier. So, here's the water... and the corn syrup. Whoa. That's why the water is able to float on top of the corn syrup. And here's the oil. The oil is lighter than the water and that's why the oil can float on top of the water.