Common Room Resonance of the Human Body

Common Room and common capers,
Sitting, talking over papers,
Common students in common strife
Battle against a common life.

Each has his own identity,
Each but lost in community;
Each has something to contribute,
Each but little lasting tribute.

A restless movement here and there,
The piano helps to clear the air;
A beat, sure gone, goes for the door
While regular feet slide the floor.

Yet contrast dress, different manners
Distinguish players from planners;
For each his life—but common doom,
In the new Common Common Room.

—By Nitram.

Vibrations and resonances have been studied in various structures for centuries, but it is only recently that man himself has been looked upon as a spring-mass system. The development of high-speed aircraft in which a crew has to work under difficult conditions has stimulated interest in human body resonances. A number of experiments have been carried out to find how intensity of vibration, body size and muscular tension influence resonant action of the body.

Spinal resonances, measured with accelerometers, occurred at 5, 2.4, and 13 c/s., the first one being the most marked. This was found to be very uncomfortable, and tests on the recording of printing errors, and the co-ordination of hand and eye movements showed significant degradation in performance; although it was even worse below resonance at about 4c/s.

Tests on 10 men have shown that variation in body size and intensity of vibration has little effect on resonant frequencies, but that muscular tensing diminishes involuntary shoulder - shrugging movements and raises the frequency slightly because it increases body damping.

It is interesting to note that resonance induced in motor-cars by road shocks is of about the same frequency as the resonance frequency of the human body. These experiments may well explain why some cars give better rides than others although there is no obvious difference in springing.

G.J.N