Vibroscope

Vibroscope (Latin: vibrare 'vibrate' + scope) is an instrument for observing and tracing (and sometimes recording) vibration.

[1][2] For example, a primitive mechanical vibroscope consists of a vibrating object with a pointy end which leaves a wave trace on a smoked surface of a rotating cylinder.

For examples, polymers' torsional modulus and Young's modulus may be determined by vibrating the polymers and measuring their frequency of vibration under certain external forces.

[4] Similar approach works to determine linear density of thread-shaped objects, such as fibers, filaments, and yarn.

[6] Jean-Marie Duhamel published about an early recording device he called a vibroscope in 1843.