This is now in the age of technology, when all thermometers are electronic and run on batteries, it is impossible to break it and there is no danger from it, but in my childhood we used only mercury thermometers and I even broke one once, and it was very scary for me then, because my parents said that if I break it, I will have to move out of the house for a month so that all the danger has dissipated. But in fact, they just cleaned it up and nothing serious happened.
