posted by teresa .
how do you calculte the volume of a single drop of water??
Actually you don't; however, there are some good estimates. Most good burets with ground glass ends will deliver very close to 30 drops/mL. Most good burets with normal tips will deliver very close to 20 drops/mL. Therefore, the volume would be 0.033 to 0.05 mL/drop depending upon the type of buret you have. One of the first things I always suggested my students do was to count the drops in 1 mL using the buret they expected to use for the remainder of the semester, then calculate the volume of one drop. Many counted for 2 mL or 3 mL and took the average. That turns out to be no "guess" but a quantitative measurement.