The higher pressure inside a balloon pushes outward and keeps the balloon in a round shape when inflated.
When air moves quickly, it doesn’t have time to push on a surface, such as an airplane wing. The air just zooms by, barely having time to touch the surface, so not much “air weight” (pressure) gets put on the surface. Less weight means less force on the area. You can think of “pressure” as force on a given area or surface. Therefore, a less or lower pressure region occurs wherever there is fast air movement.
Here’s a video to get you started:
(Please note that this is live footage from a science camp taught to hundreds of kids! Since we didn’t record this video in a studio, just ignore the blips, shakes, and odd angles and focus instead on the real science behind it.)
There’s a reason airplane wings are rounded on top and flat on the bottom. The rounded top wing surface makes the air rush by faster than if it were flat. When you put your thumb over the end of a gardening hose, the water comes out faster when you decrease the size of the opening.
The same thing happens to the air above the wing: the wind rushing by the wing has less space now that the wing is curved, so it zips over the wing faster, and creates a lower pressure area than the air at the bottom of the wing. Let’s do some experiments to really bring these concepts alive.