When heated, the molecules of the liquid in the thermometer move faster, causing them to get a little further apart. This results in movement up the thermometer. When cooled, the molecules of the liquid in the thermometer move slower, causing them to get a little closer together.
Thereof, how do thermometers work by thermal expansion?
When a substance gets hotter, it expands to a greater volume. Nearly all substances exhibit this behavior of thermal expansion. It is the basis of the design and operation of thermometers. As the temperature of the liquid in a thermometer increases, its volume increases.
Beside this, how does a thermometer work short answer?
A thermometer has a glass tube sealed at both ends and is partly filled with a liquid like mercury or alcohol. As the temperature around the thermometer’s bulb heats up, the liquid rises in the glass tube. … When it is hot, the liquid inside the thermometer will expand and rise in the tube.
Why does liquid rise in a thermometer?
1. The liquid in the thermometer goes up when the thermometer is heated because heating makes the alcohol molecules of the liquid move faster. The extra speed of the molecules competes with their attraction for one another and causes them to move slightly further apart.