How a boat floats...

Some materials, such as wood, float in the water, other materials, such as steel, sink in the water. Since the beginning of time people have found materials that float in the water to travel on. But, as many of you probably know, today we can travel on a ship made of steel. If we just drop a piece of steel in water we will see that it the piece of steel will sink. So we ask ourselves, how does this floating thing work?

Archimedes, a mathematician who lived from around 287- 212 B.C., was the first person to record anything about why things float, other wise known as buoyancy. One day when he sat in his bath some of the water spilled out.  He also noticed that his body felt lighter in the water than out of it. He decided that the reason his body felt lighter was because the loss of his weight must be equal to the weight of the water that spilled out of the bathtub.

So, when you place an object into the water the object pushes down with pressure on the water and the water pushes back up with force on the object. If the object puts more force on the water than the water can put back on the object then the object will sink. If the water puts more force on the object than the object can put back on the water, then the object will float.

You can take an object such as a block of steel which would normally sink and reshape it so that it will float.

 

This makes it so that the same amount steel is spread over a larger amount of area in the water. This means that there is more water to exert more pressure on the same amount of steel causing the steel to float.