Robert W. Mellette
TOPIC: Bernoulli’s Principle
Rationale In 1738 Daniel Bernoulli published a paper entitled HYRODYNAMICA.
This work was on pure and applied fluid notion. One concept discussed in this work is the principle that, “the higher the speed of a flowing liquid or gas, the lower the pressure. Bernoulli’s principle can explain the “LIFT of an airplane wing or in this case why a coin seems to magically fly up from a desk and land in a nearby saucer.
Objective To have students perform a simple experiment that demonstrates in a dramatic way a basic principle of aerodynamics the concept of LIFT.
Materials Required
A coin (dime)
A small saucer or plate
Procedure Place a dime about 1/2 inch (13mm) from the edge of a desk. Position a saucer or small plate a few inches (5cm) from the coin as shown in figure 1. Blow a quick, strong blast of air across the top of the coin. With practice, the dime will “jump” into the air and land in the saucer.
Fig. 1
(figure available in print form)
Conclusion This “magic trick” can be explained using a principle that was discovered by a scientist over 250 years ago. In 1738, Daniel Bernoulli stated that an increased flow of air would create an area of lower air pressure over a surface. The sudden,swift movement of an air-stream over the coin creates an area of low pressure. The atmospheric pressure in the room rushes in to fill the area of low pressure. This force provides the “LIFT” which causes the coin to rise up into the air and land in the saucer.