Metal Rod Conduction

A metal rod is heated at one end, and pieces of wax attached along its length melt one by one. This demonstrates how heat is conducted through the solid from the hot end toward the cooler end.

1. Attach small pieces of wax at equal intervals along the length of a metal rod.
2. Secure the rod horizontally so that it is stable and safe to heat.
3. Heat one end of the rod using a Bunsen burner or candle flame.
4. Observe how the wax nearest the heated end melts first, followed by wax pieces farther away.

Heat transfer demo conduction through a metal wire - Janne Tamblyn Lee:

Conduction Experiment | Heat - ExperiHub:

• Use rods made of different materials (copper, iron, aluminum) to compare conduction rates.
• Replace wax with small pins stuck into wax blobs; as the wax melts, the pins fall.
• Try rods of different thicknesses or lengths to see how this affects the rate of conduction.

• Safety glasses required when using an open flame.
• Use heat-resistant gloves to handle the rod after heating.
• Ensure the rod is securely supported to prevent it from rolling or falling.
• Do not touch melted wax immediately, as it can cause burns.

• Why does the wax closest to the heated end melt first? (Because heat travels by conduction from the hot end to the cooler end.)
• How does the melting sequence demonstrate the direction of heat transfer? (It shows that energy moves progressively along the rod.)
• Would a glass rod produce the same result? (No, glass is a poor conductor, so the wax would melt much more slowly, if at all.)
• How do free electrons in metals help explain why metals conduct heat well? (Free electrons transfer energy quickly by colliding with atoms, speeding up heat transfer.)