Organ Pipe Demonstration Model

Quick Answer: The Organ Pipe Demonstration Model is a set of metal pipes of graded lengths hung from a frame on a base, used to show how the length of a pipe determines the pitch of its note. It supports lessons on resonance, standing waves and the difference between open and closed pipes.

Pipe Length and Pitch

In the listing image, the organ pipe demonstration model has several metal pipes of different lengths hanging side by side from a cross-bar above a labelled base, arranged from longest to shortest. Lined up this way the pipes make the main idea obvious at a glance: the longer the pipe, the lower the note. Students can sound each pipe in turn and describe the change in pitch before they meet any formula.

A pipe sounds its note when the column of air inside resonates. In a pipe open at both ends, the fundamental standing wave fits half a wavelength into the pipe, so the frequency is the speed of sound divided by twice the length. A pipe closed at one end fits only a quarter wavelength, so it sounds about an octave lower than an open pipe of the same length and produces only the odd-numbered harmonics. Real church and concert organs use both types.

It is worth being clear about how the pipes are sounded. Blowing across an open end, or holding a vibrating tuning fork over it, excites the air column. Striking a hanging metal tube with a beater, as in a set of chimes, makes mainly the metal itself ring, and its pitch follows different rules. Both effects show that longer means lower, and the comparison makes a good discussion point. The labels in the image mention an adjustable pipe; which pipes adjust, and how, should be confirmed at enquiry.

Using the Pipes in Sound Lessons

• Ranking the pipes by pitch and relating pitch to length
• Finding resonance by holding a tuning fork over the open end of a pipe
• Comparing the notes of open and closed pipes of equal length
• Estimating the speed of sound from pipe length and a known frequency

Specifications

Care & Handling

• Strike or sound the pipes gently; heavy blows dent thin metal and change the note.
• Wipe the pipes with a dry cloth to remove fingerprints and prevent tarnish.
• Check the suspension cords regularly and replace any that fray.
• Store the frame upright so the pipes hang freely and do not knock together.

Why Choose LabEquip

Physics teachers covering waves and sound, and music teachers explaining how instruments work, both use a set of graded pipes. LabEquip lists this model in the STEM kits range, with the Bell in Jar with Air Pump for showing that sound needs a medium to travel. Contact us via the contact page.

Frequently Asked Questions

Why does a longer pipe give a lower note?

The air column in a longer pipe holds a longer standing wave. Because the speed of sound in air is fixed at a given temperature, a longer wavelength means a lower frequency, and we hear a lower frequency as a lower pitch.

What is the difference between an open and a closed pipe?

An open pipe is open at both ends and its fundamental has half a wavelength inside it. A closed pipe is sealed at one end and holds only a quarter wavelength, so it sounds roughly an octave lower and produces only odd harmonics.

Does striking a pipe test the air column?

Not really. When a hanging metal tube is struck, most of the sound comes from the metal walls vibrating, like a bell or chime. To study the air column, blow across the open end or hold a sounding tuning fork over it.

How can students estimate the speed of sound with a pipe?

If a pipe closed at one end resonates strongly with a tuning fork of known frequency, its length is close to a quarter of a wavelength. The speed of sound is then about the frequency multiplied by four times the length, with a small end correction for the pipe’s diameter.

Why does temperature change the note of a pipe?

Sound travels faster in warm air, so the same pipe length produces a slightly higher frequency on a hot day. Organ builders and wind players tune their instruments at the temperature they will be played in for this reason.

Which age groups is the model suitable for?

Younger pupils can order the pipes by pitch and length, while senior students calculate frequencies, discuss harmonics and compare open and closed pipes. The model also suits music lessons on how wind instruments work.

Last Updated: September 2026