Things float in water because of something called density! It's all about how much "stuff" is packed into a certain amount of space.
What is Density?
Imagine you have a box. If you fill the box with feathers, it will be light. But if you fill the same box with rocks, it will be heavy. The box of rocks is more dense because it has more "stuff" (rocks) packed into the same amount of space.
Density and Floating
Water also has density. Here's the simple rule:
- If something is less dense than water, it will float. Think of a light piece of wood.
- If something is more dense than water, it will sink. Think of a heavy rock.
Examples to Help You Understand
| Object | Density Compared to Water | Does it Float? |
|---|---|---|
| Wooden Block | Less Dense | Yes |
| Rock | More Dense | No |
| Rubber Duckie | Less Dense | Yes |
| Metal Spoon | More Dense | No |
| Big Cargo Ship (Made of Metal) | Less Dense Overall (because of air inside) | Yes |
Why Big, Heavy Ships Float
You might be thinking, "But ships are made of metal, and metal sinks!" That's true! However, ships are designed with a lot of empty space inside. This empty space makes the overall density of the ship less than the density of water, so it floats! The air inside the ship is what makes it buoyant.
Conclusion
So, whether something floats or sinks depends on its density compared to water. If it's less dense, it floats! If it's more dense, it sinks! Density is like how much "stuff" is packed into something.
