Understanding Gas PressureFigure shows a boy pressing the front tyre of his bicycle. (a) When he presses the tyre with his thumb, he feels an opposing force acting on his thumb. (b) The force is due to the air pressure in the tyre. (c) The air pressure is due to the collisions of air molecules in the tyre against the wall of the tyre. Figure shows air molecules in … [Read more...] about Understanding Gas Pressure