Thermal race

Heat for speed!

15 minutes


  • Carefully review the general safety advice on the back of the box cover before starting the experiment.
  • Observe safety precautions when working with boiling water.
  • Avoid touching heated objects with bare hands.


  • Dispose of solid waste together with household garbage.
  • Disassemble the setup after the experiment.

Scientific description

If one object heats another only at their point of contact, how do large or long objects end up heating up entirely? At the point of contact, the fast molecules  of the warm object collide with the slow molecules  on the surface of the cold object, pushing them to move faster .

Next, these faster molecules  in the cold object collide with the adjacent molecules in the deeper layer of the cold material, pushing the slow molecules  there to also move faster . Thus, the temperature of the object gradually rises as the speed of its molecules increases.

When heated in one place, an object gradually becomes the same temperature throughout its volume. An object’s ability to spread heat or cold through itself is called thermal conductivity. The rate at which heat or cold is transferred along an object depends mainly on its material.

For instance, the copper “heat pipe” transfers heat very quickly. Such materials are used in devices to cool elements that heat up  during operation. With the aluminum tube, heat spreads noticeably slower. Materials that don’t transfer heat  well are used as insulation to prevent cold from entering a building, and heat from seeping out.