Hi, We learned that, air pressure in a closed container is actually related to the quantity and speed of gas molecules hitting on the container's walls. So kinetic energy of the molecules determines the air pressure. However, isn't the fact that air pressure decreases when the speed of gas increases contradicting with the statement above? For example, let's think of two balloons hung side by side. When we blow air between them, they get closer to each other due to the fact that the air pressure decreases when the speed of air increases. But, when we blew the air, doesn't also the speed of air molecules increase, in that the kinetic energy of the molecules increase? If so, we would expect the air pressure to increase when we blow, so the balloons should move away from each other. Why doesn't it happen like this? Thanks in advance.