Have you ever seen a submarine? Of course we know that in designing the submarine must pay attention to the hydrostatic pressure of seawater. This is a consideration in designing the structure and selection of materials to make the submarine.
One material that is resistant to hydrostatic pressure is very large sea water is steel. Did you know that steel is the metal is mainly made of a mixture of iron and carbon?
Thus the steel has a density greater than mass type of sea water. Think about why submarines and other ships made of steel do not drown, even though the density of steel is much bigger than that of the sea?
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Archimedes
After you look at the Archimedes experiment, you can tell that when an object is inserted into water, its weight is reduced. This event does not mean there is a mass of missing objects. The weight of the object is reduced when put into water, caused by the buoyant force (Fa) that push objects up or against the object's weight.
This phenomenon was studied by Archimedes whose results were later expressed as the law of Archimedes as follows:
"If the object is immersed in a liquid, then it will get an upward force as large as the weight of the liquid pressed by the object."
According to Archimedes, things become lighter when measured in water than in the air because in the water the body gets upward. When in the air, the object has a weight approaching that indeed.
The laws of Archimedes are used as the basis for shipbuilding or submarines. An object can be floating or drowning depending on the magnitude of gravity (w) and buoyancy (Fa). If the maximum buoyant force is greater than gravity then the object will float.
Conversely, if the maximum floating force is less than gravity then the object will sink. If the maximum floating force is equal to the weight of the object, then the object will float. The maximum buoyant force is buoyant force if the entire body is below the liquid surface.
Almost all metals have density (density) larger than water. Of course you think that all metal will sink in water. Why are ships made of metal not drowning? Ship floats can be floating because when placed upright in the ocean, ships can move sea water in large enough quantities, so the ship gets the same upward force with the weight of the ship.
The concept of a submarine
What about the submarine? How can a submarine float, float, and sink in seawater? In principle
the submarine can have that ability because the submarine's weight can be enlarged by inserting water into the ship's body and can be minimized by removing water from the ship's body.
When the submarine will sink, the seawater is put into a container inside the ship's body. The total weight of the submarine becomes larger than the upward force, so the submarine can sink. In order not to continue to sink, at some depth the water within the submarine body is removed from the container, so the total weight of the submarine equals the upward force.
This matter causing the submarine to float in the water. When the submarine will float, water from the shelter on the ship's body is removed so the total volume of the submarine becomes smaller than the upward force, so the submarine can float.
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