Molecular Conduction
Physics: Cambridge International GCSE Supplement, topic 2.3.2
How Conduction Happens
There are two mechanisms for conduction in a solid:
Lattice vibrations
- If one part of a solid is heated, the particles in that part gain energy and vibrate more.
- These vibrations then transfer heat energy to neighbouring particles which also vibrate more.
- The closer particles are together (in a more dense solid), the better the solid will conduct heat energy.
Electron transfer
- Metal lattices contain free (delocalised) electrons that can move anywhere in the lattice.
- These electrons gain heat energy in the hot part of the object and carry it to other parts of the lattice.
- Solids with more free electrons are better thermal conductors.
Gases and liquids
- In liquids and gases, particles are much farther apart.
- Because of this large spacing, collisions between particles happen less frequently, so energy transfer is much slower.
- In gases, the spacing is greatest, making them the worst conductors.
Test yourself on Molecular Conduction
Why do you feet feel colder on tiles than carpet?
Which of the following are true of conduction in metals?