Explain how a ship made of materials that are much denser than water is able to float on water?

Question

anonymous · Answer

Can you explain this question?

blues · Answer

Pretty much all ships are made out of materials which are denser than water. If you put a piece of steel in water, it will sink. Though most pieces of wood will float initially, once they become water logged they will sink also. So the question asks, "If the stuff ships are made out of all sink when put in water, why does the ship not sink?"

anonymous · Answer

Because the weight is evenly distributed?

blues · Answer

Hmm, the weight is evenly distributed in a steel bar. Yet if you put the steel bar in a bucket it will go straight to the bottom.

Think about a ship - it is water tight, so it is full of air. If it springs a leak, water rushes in. It is no longer full of air. And then it sinks...

anonymous · Answer

Well then it's because the air filling the ship makes it more buoyant versus a piece of steel has no air inside???

blues · Answer

That is the informal, non scientific reasoning. Because the ship is so full of air, it displaces a large volume of water when it floats. Think about how buoyancy relates to volume of displaced fluid. Because it displaces a large volume of water, it is really buoyant...

anonymous · Answer

ohh that makes so much sense! Thanks you! This lesson was giving me trouble but now its not!

blues · Answer

And to finish up, think about what happens when the ship springs a leak. All the water rushes in. Now it displaces a very small volume of fluid - just the total volume of the pieces of wood or steel or whatever it is made out of - so it not buoyant anymore. So it sinks. :D