Eli5 what determines buoyancy of an object

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What makes things float?

In: Physics

2 Answers

Anonymous 0 Comments

When you immerse an object in water you are claiming a space that would otherwise be filled by water. So where does that water go? Up! Just like a baseball wants to drop down if you let it go, that displaced water is competing to reclaim its space by going down. In the process it is pushing the object upward. If the weight of that object is smaller than the liquid it displaced, it will be balanced by only pushing it partly above the surface of water. This is the so called “floating”

Anonymous 0 Comments

The answer is density. Density means how much does the object weigh per unit of volume – or in simple terms, how much each tiny element of the object weighs.

The denser the object, the harder it is for the water to “hold it up” against gravity, and so if it is more dense than water it will sink.

The cool thing is that the factor is density and not weight. So a ship can be really really heavy but if it’s large enough, it could float.
But fruit which could be pretty light would sink because they are very dense.