Mercury thermometers have fallen out of favor especially for home use because mercury is toxic and thermometers are made of glass, which tends to break. Alcohol thermometers can be used, but for those who prefer a liquid metal look, a recent invention is the "galistan" thermometer, which uses a patented eutectic alloy of gallium, indium, and tin, liquid down to below the freezing point of water. (Which means there's no problem using it to measure the temperature of anyone who isn't dead.)
This patent explains all about the alloy and its advantages in the construction of thermometers.
Unfortunately, like all gallium-indium alloys, it's kind of sticky, which makes it much less fun to play with than mercury. It's also hugely more expensive, which isn't a problem for the tiny amounts needed in a thermometer, but is a big problem if you want to make a few pounds of it to play with.
Source: Grocery Store
Contributor: Theodore Gray
Acquired: 10 November, 2003
Text Updated: 11 August, 2007