The only two ways that come to mind are a temperature increase in the tank, or an increase in pressure in any feed lines supplying the tank.
exspanion tank or relive valve
The pressure will increase
It would rise
No
if the well pressure switch goes with the tank then the second floor pressure would more closely match the well pressure setpoints and the ground floor would have slightly higher pressure. with the tank and pressure switch on the lower floor the lower floor would more closely see the well pressure setpoints and the second floor would get slightly lower pressure.
decrease the temperature or increase the volume
A bubbling noise in a well pressure tank is a sign of a hole in the tank. It means that air is getting into the tank and causing air to bubble through the water.
An increase in temperature would cause air pressure to rise. As air warms, its molecules gain more kinetic energy and spread further apart, leading to an increase in pressure. Cold air entering a region or moisture entering the air would not directly cause air pressure to rise.
Assuming the tank was not in a vacuum, the VOLUME stays constant. The volume is the total area inside the tank. The pressure would change when 'pumped up'. The volume would not. The pressure inside would also change based on the temperature, relative to the outside pressure.
No you don't need a tank to simply pump water from a lake. You would only need a tank if your using a pressure switch to turn the pump on and off.
If the tank is not strong enough to withstand the pressure underwater, it can collapse or deform, leading to a decrease in volume. This loss of volume could result in the tank failing to contain the intended contents or even causing environmental damage if it leaks. It is important for the tank to be able to withstand the pressure to maintain its integrity.
A fuel tank pressure sensor is a device used to measure the pressure in a fuel tank.