So that you can see it more clearly.
We still use colored alcohol for our liquid in everyday thermometers.
Thermometer
If the last word was meant to be "alcohol", then the answer is a thermometer.
If the last word was meant to be "alcohol", then the answer is a thermometer.
If the last word was meant to be "alcohol", then the answer is a thermometer.
It is a glass thermometer.
It is a glass thermometer.
Thermometer
It is a thermometer, used for recording temperature.
Modern thermometers don't use mercury, they use a colored alcohol solution... and yes it would be dangerous.
For a classic thermometer: glass and mercury, colored ethanol or another liquid.
The heat on the outside of the thermometer transfers to the glass which transfers to the alcohol making the alcohol expand making it rise