Duff's Inclined Plane - Physics Demonstrations - Duff's Inclined Plane | Physics Undergraduate Labs

Lycopodium powder is highly flammable when dispersed in air. Keep away from open flames, hot plates, and electrical sparks. Use minimal quantities and clean up spills immediately. Consider using non-flammable chalk dust as a safer alternative for routine demonstrations.

Purpose

A steel ball rolls down a tilted curved trough, leaving a sinusoidal trace in lycopodium powder. The half-wavelengths mark equal time intervals, and measuring successive spacings shows they increase by a constant amount — confirming uniform acceleration.

Black wooden trough with a sinusoidal white powder trace whose wavelength increases from left to right, flanked by two meter sticks, with a wooden block elevating the left end

Figure 1: Sinusoidal trace left by a steel ball rolled in lycopodium powder. The increasing half-wavelength spacing from left to right demonstrates constant acceleration down the incline.

Safety Warnings

Warning: Lycopodium Powder Handling

Purpose