Depends on what valves your tubes are equipped with.
See link below for descriptions and how they work
Air fille bicycle tires were invented by John Dunlop.
actually bicycle tire or for that matter any kind of tire does lose air, the heat in the summer causes the air in the tires to expand. That's why is not a good idea to fill your tires to the max in the summer time.
Usually the pump or compressor just takes air from the surrounding and pushes it into the tube/tire.
I'm assuming you're referring to the tubes in the tires here. The purposes for using air-filled tubes in bicycle wheels are comfort, traction and weight. W/o air filled tires, the option is solid tires, and solid tires gives a harsher ride on uneven surfaces, poorer traction and a higher weight.
They smooth out bumps on the road. Let all the air out of your bicycle tyres and then ride it if you don't belive it.
There is no single answer to this--bicycle tires vary a lot. The maximum p.s.i. should be written on the sidewall. "Fat tire" cruisers are frequently about 35 psi; the narrow tires on road bikes sometimes go up to 120 psi.
If all other things remain the same, a higher temperature means a higher pressure. For bicycle riding, the difference isn't enough to matter.
It's there to cushion the ride. An air chamber is light, and dampens out vibrations from the road better than(most) solid tires. Air filled tubes would act as shock absorber. It is nice and fluid, makes the tires soft and able to absorb bumps and impacts.
Basic physics ! Friction between the tyre and the road creates friction. This heats the trapped air within the tyre.
The answer to that would differ a lot depending on what tire you're thinking about, and what the pressure is. Tires come in very different sizes, with very different volumes.
When you are not sitting on it.
Car tires have very stiff sidewalls, that can carry some of the load. Bike tires are flimsy and have to do it all by air pressure. Besides, om a bike, with the power restrictions of its human engine, it becomes more important to keep the rolling resistance down as much as possible.