How do ships float?

BALTIMORE (Map, News) - If you put a fork, spoon or another metal object in a bathtub, it will definitely sink.

Then how do the enormous metal ships in the Inner Harbor — which weigh a lot more than a kitchen utensil — stay afloat?

Well, the answer is based on the idea of water displacement.

When you climb in to the bathtub, the water rises because your body is taking up space. Similarly, when a ship is placed in water, it makes the water level rise, although you would never notice it!

The logic behind this principle is that ships float when the weight of the water displaced is exactly the same as their own. The ship would sink if it was small but weighed a lot, like a brick.

This brings us to the next factor that determines flotation: density. A brick or a solid piece of metal is a heavy object that displaces only a little water. However, steel ships float because they have a large empty space inside, which decreases their average density. The weight of ships is spread over a large area, therefore displacing a lot of water.

Want to know how something works? Send an email to Anna Minkowski: aminkowski@baltimoreexaminer.com.

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