Question #b58a7

1 Answer
Apr 13, 2015

This is due to a phenomenon called Thermal Expansion that occurs in materials when temperature rises.
You may think at mercury as a group of, say, students sitting at their desks in a classroom. They oscillate and move around their chair (trust me I know that because I teach and it is difficult to maintain them still!) and when you increase the temperature it means that they receive energy and start to oscillate more and more.
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Now in the first case you could measure the width of your classroom of students as x but when they start to oscillate you'll measure a larger width due to the fact that your students now occupy a larger area (oscillating).
Mercury does the same and to cope with the increase of volume (in this case) it rises up the glass column when temperature increases.