Have you ever wondered why the ship does not sink? If you build a raft of wood, then he can safely sail through the water. But if you make it from metal or stone, it will sink to the bottom. Explain this phenomenon is not difficult. After all, the density of stone or metal is different from the density of wood. This is told in physics lessons. The fact is that the density of the tree is much lower than the density of the metal. Moreover, the expelling force of water is much higher than the exponent of gravity, which acts on the raft. With metal, everything is somewhat different. Its density is high enough, and buoyancy is not able to overcome the force of gravity. As a result, the raft is sinking. But why does the ship not sink now, when they are made of metal?
If sheathe a tree
In the old days, ships were built only of wood. But everything is changing. Now ships are built from a more reliable and strong material - metal. But why doesn't the ship sink? Does it turn out harder? What is the reason? Is there more wood than metal inside the ship?
If you take a tree and sheathe it with very thin sheet metal, then the structure will not sink. This phenomenon can be explained by making some calculations. So, the average density of the structure will be less than the density of water. Here are the simple numbers. If you take a tree mass of 100 kilograms at a density of 600 kilograms per cubic meter, and metal cladding weighing 20 kilograms and a density of 7800 kilograms per cubic meter, the total weight of the vessel will be only 120 kilograms, and the volume will be 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 about 714 kilograms per cubic meter. This indicator is less than that of water. This suggests that the wooden vessel, previously sheathed with sheet metal, will not sink. After all, the density of water is 1000 kilograms per cubic meter.
Modern designs
The design of the ship is quite simple. You can not sheathe wood with metal. It is enough to leave an empty cavity inside the structure into which water will not enter. Of course, this expression is a little 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 is why the ship does not sink, being at a great depth. Indeed, inside the structure there are large cavities that are filled with air. Due to this, the density of the entire ship is much lower than the density of water. As a result, the buoyancy force keeps the structure afloat.
Why doesn't water 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 located under water. As a result, compartments form. At the same time they are made airtight. Due to this, water falling into one compartment cannot get into the second. If a hole appeared in the hull, the vessel will not go to the bottom. Only the compartment where the water enters will be flooded. The rest will remain filled with air.
How to transport goods
The ship, as a rule, has weight. And it is equal to the mass of water, the volume of which the ship occupies at sea. Of course, an ocean ship is unlikely to sail empty. Usually not only people are transported by ship, but also large loads. An empty ship weighs significantly less. This means that it will also be shallow in water. If the ship is loaded, then it will settle more. But why does the ship not sink even with a heavy load?
Usually a line is drawn on the hull of the vessel - the waterline. The ship should not be submerged below this indicator. Otherwise, it will be overloaded, and any large wave can flood the structure.