Water pressure refers to the pressure of water in a system. In a home it will be 30-50 psi typically and this is governed by the municipal pressure or by a well tank.
Saturated steam is gas-phase water in equilibrium with liquid water at the same temperature and pressure. If the temperature is above the saturation point and/or the pressure is below the saturation pressure, the steam is "superheated steam". In either case it is a gas. There are some conventions where saturated steam along with some fraction of liquid water in equilibrium with it is still referred to as steam even if not all of it is gas, as long as at least some of it is gas.
Flushometer type needs at least 30 PSI to operate semi decently 50 PSI or more would be ideal
House water pressure should be around 50-60 psi.
No and yes. No, you won't get more water pressure. To do that you'll need to find out why the water pressure is low. Perhaps flow restriction, perhaps a poorly adjusted water pressure regulator, perhaps low pressure from the well/city water. But an additional water heater will certainly give you more hot water. It would be like putting in a LARGER water heater. In most cities the water pressure required is about 20 PSI. Small city's do not add pressure pumps to their system but use a gravity supply. That is why most places there is a pressure problem either build their water tanks taller or erect them on a hill.
at sea level
The pressure at the bottom of the bottle is the greatest. It decreases as the level comes up and is the least at the top.
Yes, at least at 1 ATM pressure.
Gravity. Water will always take the path of least resistance, which is sideways. And if there is pressure from the top, Pascal's principle is in affect which states that when pressure is applied to the top of a body of water the resulting affect is pressure on all other sides of the body of water.
This does vary slightly according to the shower, but for a shower without a pump, using a gravity feed, a water pressure of at least 0.1 bar is recommended. If your water pressure is low you will need to install a pumped shower.
The water in artesian wells is under pressure - or at least was when the well was dug.
It needs at least 38 psi of incoming water.
You need some sort of an instrument. Most of us just use a pressure gauge, although you could do it empirically--you could throw the end of the hose in water, and if bubbles came out you would know the gas pressure is at least as high as the water pressure--which is 15psi since the 15psi atmosphere is pressing down on the water.
You haven't provided enough information, we need to know, at least, the pressure of said pressure cooker, and even then I'm not sure quite if it's possible. If you look up the phase diagram for water, you can see that the melting point goes down with more pressure.
Bottom and top respectfully OR Greatest closest to the center of the Earth.
You need at least 50 psi, and if there is a restrictor, remove it.
Because the water is forcing bubbles from you and it is sucking all the air out of your ears which causes the pressure to hurt.