Knipp's singing tubes
Date: circa 1925
Inventory Number: 1997-1-0920
Classification: Singing Flame
Dimensions:longer tube: 0.8 × 23 × 0.8 cm (5/16 × 9 1/16 × 5/16 in.)
box: 3.6 × 25.8 × 6.1 cm (1 7/16 × 10 3/16 × 2 3/8 in.)
Accessories: wooden instrument case
DescriptionAn apparatus for demonstrating the conversion of heat energy into sound. Sound is produced by the vibration of an air column, and the pitch of the sound is linked linked to the length of the vibrating air column.
Device consists of a pair of glass tubes; each is closed at one end and contains a smaller tube which is closed at the other end. When heated at the closed end, the tube assembly behaves like a closed pipe whose effective length is the sum of the lengths of the larger and smaller tubes.
The the pitch of one tube is fixed; the other tube has a movable glass sleeve at the open end so that its length and pitch can be varied by varying the length of the tube. The variable tube has a black rubber sleeve positioned midway along its length.
The device is housed in a rectangular wooden box with a sliding panel cover, and has a paper label affixed to the front. The label reads, "F-6367 / KNIPP'S SINGING TUBES / CENTRAL SCIENTIFIC COMPANY / LABORATORY SUPPLIES / CENCO / APPARATUS CHEMICALS / 460 OHIO STREET CHICAGO U.S.A. GLASS." A partial image of the CENCO company logo is printed in red on the box cover.