I have no idea how it is possible that a boat floats. Some of them are made with concrete, or metal, and other heavy material that on their own would sink, regardless of shape. But somehow, when it’s used to build a boat, it floats just as fine even if it carries extremely heavy load.
So what is the science behind boat floating, but explained to me like I’m five? 🙂
In: Engineering
Imagine a glass of water. If you were to drop a big marble into it, it’d disappear straight to the bottom, but the water level would rise some amount. That’s because there’s been a marble’s worth of water pushed out of the way to allow the marble to be under the water, so the water level rises. The marble’s weight is heavy so it sinks to the bottom. Makes sense right?
A boat is clearly very heavy, and as it sinks into the water it pushes water out of the way, just the same as the marble. Here’s the thing though, water is also very heavy. Ever picked up a big jug of water for a water cooler? It ain’t light. And this is the boat’s secret. It’s built to have a shape that’s spread out and wide (compared to the solid lump of a marble), so as it sinks into the water, before the water reaches as high as the boat’s sides, the amount of water being pushed out of the way is *heavier* than the boat. At that point it stops sinking and floats.
If you imagine a solid block of water 1 meter by 1 meter by 1 meter, that would be 1 metric tonne. It’s heavy stuff is water.
This is like a tupperware tub in the sink. It floats there happily. WIthout actually turning it on its side and letting water flood into it, to shove it under the water requires you to push down on it on above. That’s because the tupperware tub on its own can only push a certain amount of water out the way because it isn’t heavy enough to push any more out the way.
A boat is the same, scaled up.
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