Thermal energy (Heat)

Thermal energy (Heat)

1. How does it travel?

   • Conduction
     • Two solids in contact
       • Molecules in the hotter move faster than in the colder.
   • Convection
     • Liquids and gases
       • Circular movement
   • Radiation
     • Through space
       • waves

2. Thermal conduction

   • Conductors
     • Transfer energy easily
       • ex: metal, diamond, graphite
   • Insulators
     • Don't transfer energy easily
       • ex: glass, plastic, rubber, wood

3. Effects

   • Melting
     • A solid becomes a liquid
       • Liquid molecules move faster than solid ones
   • Evaporation
     • A liquid becomes a gas
       • Gas molecules move very fast
   • Expansion
     • With heat, molecules vibrate
       • Some materials become bigger (expand)
   • Chemical changes
     • Permanent changes
       • The change can't be reversed
         • An omelette can't become a liquid egg again