KinexiaLEARN PHYSICS

Ice Melting Race

Two ice cubes, two materials, one winner. This race exposes the invisible difference between temperature and heat flow.

Safety:

Dry the trays afterward to avoid slips. No hazards beyond cold, wet hands.

Materials

  • Two identical ice cubes
  • A metal tray, cookie sheet, or baking pan
  • A wooden cutting board or thick plastic plate
  • A timer or phone stopwatch
  • A thermometer (optional)

Procedure

1

Equalize everything

Freeze the cubes in the same tray so they match in size. Let the metal tray and wooden board sit in the same room for at least 30 minutes so both start at room temperature.

2

Predict by touch

Touch each surface with your palm and note which feels colder. Predict which cube will melt first, and write it down.

3

Start the race

Place one cube on the metal and one on the wood at the same moment. Start the timer.

4

Watch and record

Every 5 minutes, note each cube's size. Which one is shrinking faster? Does the ranking ever change?

5

Declare the winner

When one cube is fully melted, stop the timer. Compare the survivor's remaining size and discuss what the result proves.

What to observe

  • The cube on metal shrinks visibly faster within minutes.

  • The metal tray feels cold to the touch; the wood feels neutral.

  • Both cubes end as water at the same temperature — only the speed differed.

Why it happens

Both trays start at room temperature, but metal's thermal conductivity is hundreds of times higher than wood's, so it pumps heat from the warm air into the ice far faster. The cube on metal melts first even though nothing is hotter — heat flow depends on conductivity, not just temperature difference. This is also why a metal bench feels cold and a wooden one does not: your hand is the ice cube, and the metal drains your heat away faster.

Try variations

  • Add a third contestant: a ceramic plate or a book. Where does it rank?

  • Insulate the metal tray's bottom with a towel — does the cube melt even faster or slower? Why?