Like the left figure, I say size of the power per unit area 1 square meter to push the aspect perpendicularly when power works to the plane touching with pressure. I have P(Pascal), and a unit of the pressure needs it.
Request of the pressure
The request of the pressure seems to become the left figure
The experiment of the balloon
When the upper figure let air, a balloon swelled out. By its letting air in the container than the pressure in the container pressure in the balloon many; hear it; it is it, and grow it by a difference of this pressure.
The water pressure / buoyancy
Pressure acts by weight of the water underwater so that pressure acts by weight of the air in the air. This pressure is called the water pressure. It is pushed back upward when I push the chip of wood underwater like the left figure. Because the water pressure to work than the water pressure to act downward in the top surface of the object upward in a lower part is bigger as for this, the reason is because the power of the upswing works to an object by this difference. The power of the direction is called buoyancy any further.
Pressure
