demonstrations:conduction_of_different_materials

Heat Conduction of Different Materials

Materials: ★★☆ Available in most school laboratories or specialist stores
Difficulty: ★★☆ Can be done by science teachers
Safety: ★★☆ Some safety precautions required to perform safely

Categories: Materials, Heat

Alternative titles: Heat Transfer in Metals, Heat Conduction Melting Wax

Summary

This demonstration shows how heat conduction varies in different materials by using rods of copper, iron, and glass. Wax is used to attach small nails to the ends of the rods, and the heat from a Bunsen burner causes the nails to drop off in the order of conductivity.

Procedure

  1. Melt candle wax and dip one end of each rod (made of copper, iron and glass) into it.
  2. Stick a small nail or pin into the wax on each rod end.
  3. Place the rods on a tripod so that the waxed ends with nails are at the top.
  4. Position the other ends of the rods into a Bunsen burner flame.
  5. Observe which nail falls off first, second, and last.

Variations

  • Try additional materials such as brass or steel for comparison.
  • Use longer rods to extend the time differences in conduction.
  • Replace nails with small beads or paper clips for a lighter load.

Safety Precautions

  • Safety glasses required.
  • Handle the Bunsen burner with care to avoid burns.
  • Do not touch heated rods until they have cooled completely.
  • Ensure rods are securely supported to prevent accidents.

Questions to Consider

  • Why does the nail on the copper rod fall off first? (Because copper is the best conductor of heat among the tested materials.)
  • Why does the glass rod’s nail remain attached the longest? (Glass is a poor conductor of heat, so it transfers energy slowly.)
  • How would using thicker rods affect the results? (Thicker rods would take longer to conduct heat, but the order of conductivity would remain the same.)