Organ Pipe with Reed - Physics Demonstrations - Organ Pipe with Reed | Physics Undergraduate Labs

This demonstration produces a very loud buzzing sound that can be uncomfortable or startling. Warn the class before activating the compressed air. The sound level may exceed 85 dB at close range. Consider ear protection for prolonged demonstrations and avoid directing the bell opening directly at nearby students.

Purpose

Compressed air drives a metal reed in an organ pipe, producing a loud buzzing tone. A lever changes the reed's effective vibrating length to shift the pitch, demonstrating the relationship between reed length and frequency.

Wooden organ pipe with rectangular body, tapered air inlet at left, duct-tape-framed viewing window in the middle, and turned wooden bell at right with pitch-control lever visible

Close-up of reed mechanism near the bell end: metal reed strip mounted between wooden blocks, with a lever arm and wing nut for pitch control

End-on view from the bell side showing the metal reed strip in the wooden channel and the pitch-control lever arm above it, with the turned wooden bell behind

Figure 1: Full organ pipe assembly. The tapered end (left) connects to the compressed air tap via hose. The viewing window (center) shows the internal reed, and the bell (right) projects sound. The pitch-control lever is visible near the bell.

Figure 2: Close-up of the reed fixture showing the metal reed strip, wooden mounting blocks, and the pitch-control lever. Turning the lever moves an arm onto the reed, shortening its vibrating length and raising the pitch.

Figure 3: View from the bell end showing the reed strip and control lever. The lever presses an arm against the reed to shorten its vibrating length.

Organ Pipe Hose

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Organ Pipe with Reed

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Safety Warnings

Warning: Loud Sound Warning

Purpose