Bernoulli Principle is really important in physics and all other types of sciences. This principle states that as the velocity of fluid increases, the pressure exerted by that fluid decreases. In practical terms it means, a slow-flowing fluid exerting more pressure than a fast flowing fluid. This means that in a moving fluid, pressure and velocity are inversely proportional. When one is high then the other is low. If the other is high then the other is low.
This is exactly why when taking a shower, the shower curtain will stick to your leg and it is because the fast moving water from the shower’s head creates an area of low pressure which causes the shower curtain which is in that area of low pressure to stick to the nearest object which happens to be your body.
The same principle also applies to the aeroplane. This is the reason why the airplane stays in the air. Lower pressure is caused by the increased speed of the air over the wing. The area of pressure under the wing is higher. Since the pressure is higher, the wing is pushed upwards. Air moves faster over the upper surface which causes the air pressure to decrease. The lower air pressure over the top of the wing gives it the lift. If some air is directed beneath the wing, the lift must exceed the weight if the aircraft needs to fly.
The final example is a blow drier demonstrating the air flow. It makes a ping pong ball float in the air. It will keep floating even if it is titled at 45°.