Why does a boat float in 291 words
Steel shouldn’t float. Yet, the biggest of ships—made of inches of hardened steel—scour the oceans of the Earth like gravity doesn’t exist. Wait, like gravity doesn’t exist… Funny I should mention that, because it is exactly by courtesy of gravity that boats float! Suppose you’re able to get your hands on an exciting glass of water. If you drop an ice cube into it, gravity will pull it down, and because the ice cube takes up space, it forces the liquid to make way. As far as the water is concerned, the only way is up, so the surface level rises. But now something else happens: gravity also pulls the water down. So, the amount of water which is displaced by the ice cube, is now being pulled down too. The water now tries to push the ice cube back up, because it is being pulled down by gravity. This goes back and forth, back and forth—until the water and the ice cube reach a settlement. The waves will disappear, the ice cube will stop bobbing (thanks to energy dissipation, but let’s skip that for now). It’s the same with an intact ship. If it’s in the water, it rises the water level. The difference is, there is so much water out there that the sea level rises negligibly. However, in terms of volume a significant amount is being pushed away by the weight of the ship. This amount of water is also being pulled down by gravity and equals the ship’s weight, thereby pushing the entire ship back up until it floats. El secreto: any boat should be wide enough to be able to displace enough water. The upward force is called buoyancy, which Archimedes understood firstly.