Bullwhip

The sonic boom produced at close range (within 5-10 feet) can reach sound pressure levels of 100-110 dB or higher, which can cause temporary hearing discomfort or damage with repeated exposure. Always wear ear protection yourself, and offer it to students in the front rows. Warn the entire class before each crack.

Maintain a minimum 15-foot radius clear zone around the demonstrator. The whip can strike objects or people if control is lost. Ensure adequate ceiling height (minimum 10-12 feet for overhead technique) or use sidearm technique in spaces with lower ceilings. Never allow students to approach while the whip is being handled.

Purpose

The bullwhip tapers from a one-inch handle to a thin ribbon over 9.5 feet. A loop sent down the whip accelerates as mass per unit length decreases, reaching supersonic speed at the tip. The "crack" is a sonic boom.

Black braided leather bullwhip coiled on green surface, with cylindrical handle and braided knot, tapering from thick braid to flat ribbon at the tip

Figure 1: The bullwhip's tapering geometry from one-inch diameter handle to 1/2-by-1/16-inch ribbon accelerates wave propagation through impedance matching, causing the tip to exceed the speed of sound.

Warning: Hearing Protection Strongly Recommended

Warning: Clear Zone Required

Purpose

Safety Warnings

Warning: Hearing Protection Strongly Recommended

Warning: Clear Zone Required

Purpose