Recall the following:
- Archimedes’ Principle: When a body is submerged/immersed in a fluid, that body experiences an upthrust equal to the weight of the displaced fluid.
- Heat energy/thermal energy is the energy possessed by objects, substances and systems due to their differences in temperature.
- In accordance with the kinetic theory of heat, temperature is a description of the average kinetic energies of the particles within an object, substance or system
Crash Course Video:
Methods of heat energy transfer
There are three (3) methods of thermal energy transfer:
- Conduction
- Convection
- Radiation
Conduction
- This form of heat transfer occurs when there is a difference in temperature of adjacent particles (atoms, molecules, etc.) in a material
- The difference in temperature implies a difference in the average kinetic energies of adjacent particles.
- The ones with higher energy bump into and transfer kinetic energy to those with lower energy
- This method is most prominent in materials, substances or systems where the particles are in close proximity (mainly solids)
Factors affecting the rate of conduction
- Cross sectional area of material (thin metal rod vs. thick metal rod)
- Length of material
- Conductive properties of material
- Temperature gradient (the change in temperature over the length of the object)
About the conductive properties of materials
- Materials with their particles in close proximity to each other are better conductors of heat
- Air is a poor conductor (referred to as an insulator) of heat as the particles are not closely packed
- Many metals make excellent conductors of heat because of their closely packed particles and the fixed nature of their chemical bonding (particles are not mutually attracted as in a liquid)