Question

Why does the clay float when made into the shape of a boat?

Answer 1

Its bitz because of the density i think.

Answer 2

Because it displaces more water thanks to its shape.

Answer 3

Right. It's the same thing with steel and aluminum. Boats use those metals, I think.

So! It's really cool actually. The buoyant force is the weight of the displaces fluid.

So, to get a huge buoyant force, you want to displace a lot of water.

For something like clay, you want a large buoyant force to hold it up.

But if you add more clay to displace more water, it just gets heavier. And the water will have less weight per volume than clay, so the buoyant force (weight of displaced water) will never greater than the clay.

But what you can do is change the shape, rather than the weight. You just want to displace more, without increasing the weight.

So you can shape it like a boat and it will be pulled down by gravity. But as it goes into the water, it displaces quite a bit. So the buoyant force decreases.

So the boat shape means you can displace more water without increasing the mass. You can have more water weight displaced with a lesser clay weight.

The next two drawings show what I mean by "displaced water."