- Thermometric Properties
- Defining A Temperature Scale
- Laboratory Thermometer
- Clinical Thermometer
- Maximum Thermometer
- Minimum Thermometer
- Three States Of Matter
- Brownian Motion
- Pressure In Gases
- Internal Energy
- Thermal Energy
- Heat Capacity
- Specific Heat Capacity
- Change Of State
- Melting and Solidification
- Boiling and Condensation
- Differences Between Boiling and Evaporation
- Specific Latent Heat
- Thermal Equilibrium
- Conduction (You Are Here!)
Conduction is the transfer of thermal energy from one place to another without any flow of the material medium.
- Metals are good thermal conductors. Non-metals (plastics) are poor thermal conductors.(they are thermal insulators)
Conduction typically requires the objects to be in physical contact with one another.
Mechanisms of conduction:
1. Atomic Collisions
- In solids, atoms or molecules vibrate about their fixed position. In a hotter region, atoms or molecules vibrate more vigorously or have more kinetic energy than those in the colder region.
- These molecules collide with their neighbours and transfer some of their kinetic energy to them. The neighbours collide with their neighbours. In this way, heat is conducted to colder regions and raised the temperature.
- This is a very slow process.
- Solids conduct heat better than liquids and gases due to their closely packed molecules.
2. Free Electron Diffusion
- On top of atomic collisions, most metals are known as thermal conductors due to their huge number of free electrons available for thermal conduction. The migration of fast-moving electrons is known as free electron diffusion.
- In solid thermal insulators, the absence of free electrons restricts thermal conduction to the vibrations of atoms and molecules within the crystal lattices.
- This is a very quick process.
Applications of conduction:
Cooking pans are often made with metals because of their good thermal conduction property. In contrast, the handles of the cooking utensils are made up of insulators to protect the hands from scalding.
Sawdust is used to cover the ice cubes from melting.