Thames & Kosmos AIR Plus Water Power Experiment Manual page 12

AIR+WATER power |
SCIENTIFIC PRINCIPLES：
When the pump moves water from the water storage tank into the pressurized air+water tank, the water
squeezes the air inside the pressurized air+water tank upward. Air is a compressible fluid. In other words, the
volume of air can be reduced by compressing it, whereas water cannot be compressed. When more and more
water is added into the air+water tank, the water takes up more and more space. Since the space within the
air+water tank is limited, the increasing volume of water compresses the air inside the air+water tank more and
more. As a result, the pressure inside increases and becomes higher than the air outside the air+water tank. This
high-pressure air pushes on the water in the air+water tank, and the water pushes outward on all sides of the
tank in an attempt to escape and resume pressure equilibrium, or balance.
After the pump first draws water into the pressurized air+water tank, and is then pumped another 40 times, more
air is pumped into the remaining fixed space occupied by the water. Thus the air pressure becomes even higher.
These phenomena include many principles from physical science:
1.
Water is incompressible, whereas air is compressible.
2. Boyle's law: For a fixed amount of gas kept at a fixed temperature, the product of the volume and pressure
is constant.
(P1 · V1 = P2 · V2)
When more air is pushed inside a fixed volume, the air pressure will rise.
3. Pascal's principle, also called Pascal's law, is a term in fluid (gas or liquid) mechanics. It states that if pressure
variation occurs in one part of a static fluid within a closed container, the pressure transfers to every part of
the fluid equally in all directions, and pushes outward on the container wall without any loss.
How much energy is stored within the pressurized air+water tank?
According to the following experiment, when the pump draws water into the pressurized air+water tank and is
then pumped another 40 times, the pressure is approximately 3.5 kg/cm
Hydro-Pneumo
(P1 : P2 = V2 : V1) P = Pressure and V = Volume
10
.
2