Pipet Bulb Adapter Novel techniques which enable students to fill pipets more effectively have been reported reeently.',z We use an adapter requiring only glass and rubber tubing and a few minutes of glass working to overcome the difficulties. The simple soft glass adapter prepared by fist-year students as described below may he replaced by better quality Pyrex T-joints. A piece of 8-mm glass tubing issealedat one end, then heated on one side so that a bubble may be blown out that side. This bubble may be polished and used as a control hole or a second piece of tubing may be attached to make a T-joint. This tube is cut to an appropriate length of about 8 em, about 1 cm protruding as the T, and then fire polished. One end of the adapter is inserted inM a pipet bulb and the other end is attached to a short piece of rubber tubing which can be placed over the end of a pipet. To operate, the bulb is squeezed with the control bole open. The hole is then covered with a finger and the desired liquid is sucked up past the etched line of the pipet. By controlled finger pressure on the hole, the liquid is drained to the etched line for transfer to the appropriate container. There are several distinct advantages to our adapter. I t is cheap and gets s t u d e k working with glass.
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rubber tube
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Harris, W. E., and Kratoshvil, B. J., J. CHEM. EDUC., 53,253 (1976). Hanson, R. H., J. CHEM. EDUC., 54,434 (1977). University of Manitoba Winnipeg, Manitoba. Canada R3T 2N2
George G. Hiekling
Volume 55. Number 8, August 1978 1 5 H
