Bullroarer from String and Ruler

A bullroarer is a simple sound-making device that produces a roaring or humming noise when spun through the air. By attaching a piece of string to a ruler (or flat stick) and swinging it in a circle, vibrations in the air create sound waves.

1. Tie one end of a length of string (about 1 meter) securely to one end of a flat ruler.
2. Hold the other end of the string firmly in your hand.
3. Stand in an open space away from people or fragile objects.
4. Swing the ruler in a large vertical or horizontal circle.
5. Listen to the deep humming or roaring sound produced as the ruler spins.
6. Experiment by swinging faster or slower to change the pitch and volume.

Making a Bullroarer out of a Ruler - Professor Chill:

📄 Bullroarer - Wikipedia: https://en.wikipedia.org/wiki/Bullroarer

• Try using different lengths of string to hear how the sound changes.
• Replace the ruler with different flat objects (paint stirrer, cardboard strip, or wooden slat).
• Decorate the bullroarer for use in science shows or demonstrations.

• Use only in open spaces to avoid hitting people, pets, or breakable objects.
• Ensure the string is tied securely so the ruler does not fly off.

• What causes the roaring sound of the bullroarer? (Air rushing past the ruler causes vibrations that create sound waves.)
• How does swinging speed affect the pitch and volume of the sound? (Faster spinning increases pitch and loudness.)
• Why does the flat shape of the ruler work better than a round stick? (A flat surface disturbs more air, producing stronger vibrations and sound.)
• Where in history or culture have bullroarers been used? (They have been used in traditional ceremonies and communication by many cultures worldwide.)