What's the best way to answer for the question from my 5 year old student: Why a heavy ship made of steel floats?

-Selina Tracy

(1). Like Tatanic, most of the time, most part of a ship is under the water. (2). I thought it was solved by an old guy called Archimedes? (3). If NASA's X-spaceship is under the water, if the Russian sub is also on the bottom of the sea, then it is because the time has not come yet. (4). By the way, even the world record Russian space station is now under the water. (5). Like Newton's apple, it is a matter of time. (sooner or later, water molecules will somehow find their way through (or around)the steel plate, I guess)

check this page...

http://www.pha.jhu.edu/~broholm/l31/node12.html

Thanks. But seems too difficult for a 5-year old girl. -Selina Tracy

(1). Thank you very much. (2). There are always smart guys out there.

(1). I will think about it and post the message later. (2). At the same time, you can check the next message here.

I'd tell your 5 year old that the ship floats because it is mostly full of air.

And, that the shape of the boat is important to help hold the air in and the water out.

The important part is that the ship holds air below the surface of the water, too!

Trying to hold that light air down in the heavy water is the opposite of trying to hold a heavy pot of water in the air...

How do those explanations fly?

If there were a Pokeman character you could use as a prop to illustrate these point, by all means use it!

(1). A pail of water (or water in the kitchen sink), a long stem wine glass. (2). Put the wine glass in the water slowly, and it should floats on the water. (3). And that is a glass ship. (4). Slowly fill the glass with water, and it should start to sink into water slowly. That means, the glass ship is leaking, and the water is getting into the ship. (5). Fill the wine glass until it fully submerged into the water. (6). So, a dry ship can float, but a ship full with water can not float. You can show this by sinking the wine glass holding side way and let the water flow into the glass. (7). At her age, it is important to know that the boat must be kept dry, and the reason why Titanic sank was because the water got into the ship through the cracks when collided with iceberg.

The steel is heaver than water.But the ship is a big hollow tank and lighter than water of the same big volume.

Because of all the air in the ship it's less dense overall so it'll float. the concept of density should be explainable

yeah ... I can see a five year old getting that