Helicopters, Propellers, and Centripetal Force: Will it fly high?

Purpose/Hypothesis

Centripetal force is force exerted by a spinning object. When objects such as gyroscopes and tops are set in motion, their spinning creates centripetal force. This centripetal force is directed toward the center point of the spinning object. As centripetal force builds momentum, it creates balance. Helicopters rely on this balance and are designed to create centripetal force with their propellers.

A hypothesis should be brief, specific, and measurable. It must be something you can test through observation. Your experiment will prove or disprove whether your hypothesis is correct. Here is one possible hypothesis for this experiment: "Centripetal force can be disturbed if the balance is disrupted, thus preventing flight."

In this case the variable you will change is the number and position of the dimes on the toy's propeller, and the variable you will measure is the toy's flight.

What Are the Variables?

Variables are anything that might affect the results of an experiment. In this experiment, the number and position of the dimes (weights) on the propellers are the main variables.

Level of Difficulty

• Easy.

Materials Needed

• Whirly toy--a propeller on a stick
• 4 dimes
• 1 roll of adhesive tape
• meterstick

Example of a whirly toy, or propeller on a stick.

Approximate Budget

$3 for whirly toy.

Timetable

20 minutes.

How to Experiment Safely

Use caution when flying the toys. Avoid contact with eyes.

Step-by-Step Instructions

1. Spin the whirly toy between the palms of your hands and carefully release it.
2. Use the meterstick to record about how high the toy jumps.
3. Tape two dimes onto the propeller of the toy, repeat step 1, and measure the height of its flight. Record the height of the jumps.
4. Remove one of the dimes and test the toy's flight again. Use caution. The flight will be erratic. Record the change in balance and flight.
5. Repeat this test with the dimes in different positions, such as those illustrated.

Step 3: Toy with dimes attached to each end of the propellers.

Step 5: Toy with dimes taped in different positions. Test the flight patterns of each position.

Troubleshooter's Guide

Problem: The toy will not fly when the dimes are attached.

Possible cause: The dimes are too heavy. Try lightweight buttons that match each other in size and weight.

Summary of Results

Did you discover centripetal force and the actions that can disrupt its effect or balance? Record your results in a chart. Describe the behavior or draw what happened so others can learn from your experiment.