Features 1、Boil the liquid with your body temperature and observe how the liquid boils and rises through the tubes into the upper container.2、It is a looped and twisted glass containing a liquid that will ''boil'' as heat is transferred from your bare hand, very interesting.3、Once leave your hand, it takes a few minutes for the liquid to cool down and return to the large bulb. This is a very interesting science toy and a great demonstration of energy transfer.4、This toy proves the vapour-liquid equilibrium, the colored liquid in the toy is a volatile mixture with a boiling point just above room temperature.5、The heat on your hands causes the liquid to boil, and the boiling evaporates the liquid into a gas. The expanding gas pushes the liquid upward, and when you release your hand, the equilibrium is re-established. The gas condenses again into a liquid and flows back down the lower bulb. Specification Item Type Thermometer Toy Material High Borosilicate Glass Product Size Approx. 16.5 x 5 cm / 6.5 x 2 in Weight Approx. 67g / 2.4oz Package List 1 x Thermometer Toy