Thermal Conductivity In Water
To demonstrate that water is a poor conductor of heat.
Dewar of water, immersion heater, digital thermometer.
An immersion heater placed at the top of a dewar of water causes the water near the top of the dewar to boil.However, heat is not readily conducted through the water to the bottom, and the bottom remains at a much lower temperature even 15-20 minutes after the water on top begins to boil. ◙