Yes.
A common alternative is coloured alcohol. But a thermometer can be made of many things. You can have one made of metal that you stick into a piece of meat that you have been cooking, to see if the temperature is hot enough inside for the meat to have been cooked.
There are also industrial theremometers that are used in furnaces. There are many ways to measure temperature.
Whatever it is made of, a thermo-meter measures thermos, [Greek for heat].
mercury
Yes
The red liquid in a thermometer is Mercury, which is usually encased in a glass tube
The first one was made in 1714.
Using a thermometer we can measure the temperature.
It generally made using fluid which expand or contract linearly with temperature such as mercury, water or alcohol. Electronic thermometer use the relation of thermal property effect electrical conduction difference to measure temperature.
It could be used to do this - it is capable of doing it. However, Mercury is poisonous and a mercury thermometer is made out of fragile glass. Thus the danger that the thermometer would break releasing mercury into the milk (which would be for a person to drink) means that a mercury thermomiter is not the temperature sensor to use in this instance.
to tell old people that have a mercury thermometer what the temperature is
A mercury thermometer is used to measure temperature.
A clinical thermometer will offer more precise calibrated readings than a mercury thermometer. The range of measurable temperature differs between a clinical and a mercury thermometer with the mercury thermometer having the wider range.
Modern thermometers are made of alcohol or Mercury, and uses the Fahrenheit scale and the Celsius scale.
Galileo invented an air thermometer in about 1600, but changes in atmospheric pressure made accurate measurement difficult. Liquids were quickly used instead and Gabriel Fahrenheit was the first to use alcohol (1709) and mercury (1714), in a thermometer.