The expansion chamber keeps the overflow The outer tube protects the inner capillary tube. The dyed alcohol it measures the tempeture The scale lines so you can read the tempature. The spherical ball to hold the dyed alchol.
When the liquid warms up the molecules spread farther apart and the liquid rises in the tube. When it's colder them molecules in the water get closer together and the liquid goes down. If the density of the liquid is high the molecules are close together.
Temperature measures kinetic energy. Temperature is measured in Celsius and Fahrenheit.