The Fantastic Flying Flarble®
You know you twist so fine
flarble1.jpg

Concepts
Forces, lift, thrust, weight, work, energy

Materials
  • A Flarble® – one per student is ideal
  • Extension – meter stick, stop watch

Procedure
1. Hold the Flarble® with the propeller up and the shaft down in your right hand between your index finger (or middle finger) and thumb. With a firm grip spin it counterclockwise. Launching a Flarble is a lot like snapping your fingers. Observe how the work you do on the Flarble causes it to move. Record your observations below:


2. By performing work on the Flarble you give it energy. With the help of your observations, explain where the energy goes.

3. The major forces acting on the Flarble include thrust, lift, weight, and air resistance. On the picture below, draw where these four forces are acting on the Flarble when it is in flight.
flarble2.jpg

4. Now experiment to see how changing the up-and-down orientation of the Flarble affects its flight. Explain your results below.


5. Next, experiment to see how changing the direction of spin from counterclockwise to clockwise affects its flight. Explain your results below.

6. Finally, experiment to see how changing which hand you spin the Flarble in affects its flight.



Results and Discussion
Summarize the flight of a Flarble. Include in your discussion the forces acting on it and how the way work is applied to it affects its flight.



Extensions
Have students determine the average range (horizontal distance) and flight time of the Flarble. Groups can do their best to consistently launch their Flarble with the same force and height each time and average the results. Each group can then compare their results with other groups to check their precision.

Explanation
Much like a helicopter, the spinning blades of Flarble provide both lift and thrust for the toy. The blades are tilted at an angle and when spun they push against the air, which pushes against them, and the force both lifts them up and moves them horizontally. Acting against the motion of the Flarble is air resistance and gravity. Air resistance acts opposite the direction of motion and gravity acts downward. The diagram below illustrates the forces on the Flarble in flight. Changing the spinning direction, up-and-down position, or hand used to spin the Flarble will change the blade orientation and cause the Flarble to fly differently.
flarble3.jpg
Figure 21: Actual forces acting on Flarble

flarble4.jpg
Figure 22: Component forces acting on Flarble

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