A kite flies because wind pushes it.
When the kite flies, the wind exerts a force on the kite. You can notice this force yourself when you are standing in the wind with your kite. The wind pushes the kite (and you). This force can be so strong that it is difficult for you to stand still. The wind wants to blow you away.
The wind pushes against the kite when it flies. He can not blow away the kite because it is tied to a string. But the wind can blow the kite upwards heavenwards because it stands slanted in relation to the wind.
What's happening?
When the kite flies, three different forces take a hand in it: the force of the cord at which the kite is tied, the power of the wind and gravity.
1. The force of the wind pushes the kite back and up.
2. The cord pulls the kite to the front and down.
3. Gravity pulls the kite straight down to earth.
The kite stands still in the wind, if:
- The wind pushes it just as much backwards as the cord pulls it forward and if
- The wind pushes the kite just as hard up in the air ad the cord and the gravity together pull it down to earth.
If the kite stands still in the air we talk about a balance of forces.
Why does the kite climb?
The kite is rising into the sky, because the wind pushes it more upwards than the string and the gravity pull it downwards.
Why does the kite at some point stop climbing?
How far the wind pushes the kite up into the air is depends on how slanted it is in relation to the wind.
When the kite stands almost horizontally (crosswise) on the wind, the wind can push the kite strongly because this way the contact surface is bigger. When the kite stands almost vertically (straight) on the wind, the wind cannot push as hard, because the contact surface is now much smaller. It is easiest if you keep the kite slightly sideways to the wind.
While the kite rises, its position becomes more and more vertical. That is why the power with which the wind pushes the kite is getting weaker the higher the kite is climbing. Precisely at the point where the force of the wind is equal to the force of gravity and the string together, the kite will stop climbing.