Nope, it's usually alcohol. Mercury thermometers posed a serious health risk for patients that bit down on them, so they switched to a more friendly substitute.
Yes they do use mercury in thermometers but it is a poisonous metallic element so you have to careful when you use one that you don't smash is because then you could get mercury poisoning.
Yes they do use mercury in thermometers but it is a poisonous metallic element so you have to careful when you use one that you don't smash is because then you could get mercury poisoning.