2006-12-17 00:55:13 · 2 answers · asked by aly 1 in Science & Mathematics ➔ Physics
When you are using the U tube, you are comparing the different densities of 2 immiscible (mixable) liquids by noting the difference in the heights (lengths) from the point of separation of the two liquids.
The density of mercury is very high [ 13.6 g per cm cubed] compared to water. Hence if you use mercury and water to compare their density: then the height of mercury will be just 1 cm while that of water is 13.6 cm. To measure a short distance of 1 cm brings with it a lot of errors in measurement.
Howevery if you use oil which has a low density compared to water, then water can give you a height of say 8 cm while the height of oil will be 10 cm, since the density of oil is about 0.8 g per cm cubed.
I hope these sample figures clear up the confusion. There is nothing to do with mercury being poisonous. If fact mercury is NOT poisonous. If you go to http://www.youtube.com and search under liquid nitrogen you will see me performing some Physics and Chemistry experiments there.
2006-12-17 03:03:35 · answer #1 · answered by pete 2 · 0⤊ 0⤋
The two main advantages that spring to mind are:
1. availability - mercury is more difficult to get because
2. mercury fumes are toxic
2006-12-17 09:16:26 · answer #2 · answered by misiekram 3 · 1⤊ 0⤋