Thermometer or barometer
The internal capillary contain mercury.
You can use a cooking thermometer to measure the temperature of your soup. These are special thermometers specifically designed to be used in food. The ones that are used for humans are not suitable for food because they contain mercury, which is a poison. If the temperature is too high for the thin glass, it will crack and spill lethal mercury into the food. The thermometers designed for cooking have no mercury and are usually electronic. Some electronic soup makers will also show the temperature of the contents while it is cooking.
A digital thermometer is less 'intrusive' - as you don't need to hold it in place for any length of time (as you would with a mercury thermometer). Digital ones give you an almost instant reading.
A mercury-in-glass thermometer is most likely to contain alcohol. However, due to safety concerns, many modern thermometers use alcohol-based solutions or other materials instead of mercury.
If it's a silver liquid it's mercury, if it's red it's alcohol (not water)
Some pool thermometers do contain mercury, but there are alternatives available that use different substances like alcohol or digital sensors. If you are concerned about the presence of mercury in a pool thermometer, look for options that explicitly state they are mercury-free.
Mercury in a Mercury thermometer is typically silver in color.
Actually anything that won't freeze or boil at the operating range of the thermometer. The most common are mercury and alcohol.
A digital thermometer uses electronic sensors to measure temperature and displays the reading digitally, while a mercury thermometer uses a column of mercury to measure temperature and has a calibrated scale to indicate the temperature. Digital thermometers are often faster and more accurate than mercury thermometers, and are also safer since they do not contain mercury.
A non-mercury thermometer is a thermometer that does not contain mercury as the temperature-sensing liquid. Instead, it may use alcohol, galinstan, or other materials to measure temperature. These alternatives are considered safer for environmental and health reasons compared to mercury thermometers.
There are many kinds of thermometer in use. Liquid in glass thermometers usually contain alcohol (dyed red or blue) or mercury (silvery coloured).