Why the ship does not sink: physics in business

Have you ever wondered why the ship does not sink? If you build a raft of wood, he can safely swim across the water. But if you make it out of metal or stone, it will sink to the bottom. Explain this phenomenon is not difficult. After all, the density of stone or metal differs from the density of the tree. This is told in physics lessons. The fact is that the density of the tree is much less than the density of the metal. In this case, the exponential force of water is much higher than the index of gravity, which acts on the raft. With metal, everything is somewhat different. Its density is high enough, and the pushing force is not able to overcome gravity. As a result, the raft sinks. But why does not the ship sink now, when they are made of metal?

If you trim a tree

In the old days, ships were built only of wood. But everything changes. Now the ships are built of a more reliable and strong material - metal. But why does not the ship sink? Is he getting heavier? What is the reason? Maybe there is more wood inside the ship than metal?

If you take a tree and trim it with very thin sheet metal, then the construction will not sink. This phenomenon can be explained by doing some calculations. So, the average density of the structure will be less than the density of water. Here are the simple figures. If we take the mass of a tree 100 kilograms with a density of 600 kilograms per cubic meter, and a metal shell weighing 20 kilograms and a density of 7800 kilograms per cubic meter, the total weight of the ship will be only 120 kilograms, and the volume of 0.168 cubic meters. It remains to find the average density of the structure. To do this, you need to divide the mass into volume. The result is approximately 714 kilograms per cubic meter. This indicator is less than that of water. This indicates that a wooden ship, previously sheathed with sheet metal, will not be drowned. After all, the density of water is 1000 kilograms per cubic meter.

Modern constructions

The design of the ship is quite simple. You can not trim the tree with metal. It is enough to leave an empty cavity inside the structure, in which water will not fall. Of course, this expression is a bit wrong. The cavity will be filled with air. After all, the density of this mixture of substances is only 1.29 kilograms per cubic meter.

That's why the ship does not sink, being at great depth. After all, inside the structure there are large cavities that are filled with air. Due to this, the density of the whole ship is much less than the density of water. As a result, the buoyancy force keeps the structure afloat.

Why water does not get inside the ship

Of course, if water gets into the cavity, the ship will inevitably go to the bottom. To prevent this from happening, partitions are made in the part of the structure that is under the water. As a result, compartments are formed. At the same time they are made sealed. Due to this, the water that has got into one compartment can not get into the second one. If a hole appears in the hull, the ship will not go to the bottom. Only the compartment where the water enters is flooded. The rest will remain filled with air.

How goods are transported

The ship, as a rule, has weight. And it is equal to the mass of water, the volume of which the vessel occupies in the sea. Of course, an ocean ship is unlikely to float empty. Usually with the help of a ship, not only people are transported, but also large loads. An empty ship weighs considerably less. Hence, and to settle in the water it will be shallow. If the ship is loaded, it will settle more. But why does not the ship sink even with a heavy load?

Usually a waterline is drawn on the hull of the vessel. The ship should not dive under the water below this indicator. Otherwise, it will be overloaded, and any large wave can flood the structure.