invantor of digital thermometer
Mercury is the metal in a thermometer.
A bimetallic thermometer has a coil of metal strips in it. The metal strips are made of two different materials that expand/contract at different rates. Because they're connected together at one end, when the metals warm up or cool down, the coil changes shape. You use a bimetallic thermometer when you want an electrical circuit to close due to a change of temperature.
daniel gabriel fahrenheit
The inventor of the mercury thermometer was Daniel Gabriel Fahrenheit. He invented it in 1714. Fahrenheit is also credited for developing the temperature that bears his name.