Buoyancy Quiz

We are doing a buoyancy experiment today. If you drop a golf ball into some dishwashing liquid, it sinks very slowly. So why does it sink in the detergent? Because the golf ball is more heavy than the liquid that’s in the container— then the detergent.

What do you mean heavier? Can you elaborate on that at all? Umm, probably more dense? Good. And if I put this in, this is saltwater… How salt is it? It's very salty, huh? This is the saltiest salt water you can make. Okay. And I think it’s a saturated solution.

What will it do? I think it would be floating. Okay, let's have a look… Ooh, oh! Excellent, so the golf ball floats in the salt water… And if you have a look, it’s like it’s just sticking out just a little bit. So what does that tell you about it? It’s just slightly less dense, right? Like it was a lot less dense when it’s higher.

Yeah, the question is if we now take the detergent and we pour it in on top of the golf ball. What do you think will happen? Will the golf ball stay where it is? Will it go down? Or will it go up? I think it’ll go down a little bit.

Yeah, why do you think that? Well? No, let’s see. What’s lighter? Maybe it'll go up. I have no idea. I think it will go down a little bit. Do you think this is going to mix with that? Well, that's what I was thinking about. I wonder if it’s gonna mix or if it’s gonna layer itself and just sort of sit on top here.

Yeah, I think this would be standing up on top. So you can make your prediction by clicking on one of the on-screen annotations, or you can click a link in the description. But make your prediction now. What do you think is gonna happen to this golf ball? Ready in three, two, one.