The very notion of flight amazes us humans even after a century has gone by since we took to the air in the December of 1904.
It gives me immense pleasure to show children the concept of how lift is produced. Not so long ago I took it upon myself to devise a simple experiment to demonstrate the compelling power of air flow over an airfoil.
I used a piece of trim and shaped to serve as a symmetric airfoil. Attach it to a stand so that it doesnt have to be held by hand. Place this device on top of a sensitive kitchen weighing scale. Note the reading on the scale.
Take a home hair dryer. Research the specifications for the dryer to find the air flow velocity from the dryer. If this cant be found, the typical air velocity of a standard hair dryer ranges between 5 m/s and 15 m/s can be used.
Run the hair dryer and point the air flow over the airfoil while it is still placed on the kitchen scale. As the air flows over the airfoil, the weighing scale reading will begin to change – it will show a drop in weight. The drop in weight is on account of the lift being produced by the air flow over the foil. It makes the wing foil become less weightier on the scale – and hence the weight drop.
The weight drop must equal the lift produced by the foil.
Lift produced, L = .5 x Cl x v^2
Turn the dryer off. As soon as the air flow over the air foil stops, the lift produced is lost and hence the weight reading on the scale goes back to its original reading.
This proves the concept of airfoils producing lift via a simple experiment.
To advance this experiment further, the angle of the air foil can be changed, different types of airfoils can be used and camber and curvature of the foil can also be changed.
