A Cheap Vibration-Free Base for Sensitive Balances A simple device for providing a vibration-free base for sensitive balances is shown in the adjoining photograph. The device is so cheap end so efficient that i t deserves popularisstion among teaching instibutions which may have in their possession several balances bought by a long squeezing of a. slender budget. The base consists of two wooden planks (just the size of the bdance, which, incidentally, provides no space for placing any object near the balance) screwed on to each other with four tennis balls (used) in between a t the corners. For the balls to sit properly a small curved indention is made on the wooden planks. A support is provided by four rubber bushes a t the bottom. provided by the tennis balls has sufficient rigidity to .The support ., , last mdefin~telyand yet filters away nearly 80yo of the vibrations caused by heavy objects bemgdropped or rough handled very near the balance. I n a typical t e ~car~ied t out a400-g weight was dropped from a definite height near a. Metrimpex Lsbof Single Pan Balance, set. to aero, and the shock felt with and without the base was observed. With the base, the oscillation from zero was just to one division, and without it, the oscillation was to five divisions. in. base was only 11 Rs (approximately $1.50). The total expenses incurred in making a 1'/. f t X 1 f t X (Please send all communications to S. R.) L. R. GANESAN MADURA COLLEGE MADURAI, SOUTHINDIA
S. RENGANATHAN THIAGARASAR COLLEGEOF ENOINE~RING MADURAI, SOUTHINDIA
Volume 49, Number 3, March 1972
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