All fluids exert pressure like the air inside a tire. The particles of fluids are constantly moving in all directions at random. As the particles move, they keep bumping into each other and into anything else in their path. These collisions cause pressure, and the pressure is exerted equally in all directions. When particles are crowded together in one part of their container, they quickly spread out to fill their container. They always move from an area of higher pressure to an area of lower pressure. That’s why air entering a tire quickly spreads throughout the tire.
Mark hadn't ridden his bike in a while. When he went out to the garage he saw the tire was flat He grabbed the tire pump and attached the hose to the tire. H pulled on the plunger of the pump the pushed down and listened as air went into the tire. He umped up and down a few more time until the tire was fully inflated and then put the pump away
As Mark pushed on the plunger was the pressure lower in the pump or the tire?