See hot and cold water mix in infrared.

Watch The Video:

Other Demos of Interest:

Kinetic Energy into Thermal Energy

Heating Water in a Balloon

Internal Friction

Teachable Topics:

  • heat transfer
  • fluid mechanics
  • thermodynamics


When mixing liquids of different temperatures, they will come to equilibrium. The cooler liquid will warm up (gain thermal energy) while the warmer liquid cools down (loses thermal energy). The energy lost by the hot water is equal to the energy gained by the cold water. Once mixed, the liquid will all be the same temperature. By looking at systems in infrared we can see their temperature and watch this heat exchange occur. 


  • hot & cold water
  • infrared camera
  • tray and paper towels


  • pour cold water into the tray.  Colder the better...
  • turn on the infrared camera and observe the tray
  • pour in hot water and watch the mixing occur

Search 'em up!