1. Chapter 14.2 – Energy Transfer
heat energy can be transferred three ways
conduction
convection
radiation
thermal conduction –
the transfer of energy as heat through a material
takes place between objects in direct contact aka touching
takes place between particles within an object

2. Chapter 14.2 – Energy Transfer
convection –
energy transfer resulting from the movement of warm fluids
fluids are both liquids and gases
hot air rises, cold air sinks
hot air is less dense, cold air is more dense
convection current –
movement of matter that results from differences in density
may be vertical, circular, or cyclical
a heated fluid rises, cools, and then falls

3. Chapter 14.2 – Energy Transfer
radiation –
energy that is transferred as electromagnetic waves
electromagnetic waves –
visible light, infrared radiation, ultraviolet rays, microwaves
infrared radiation –
heat radiation
radiation is the only way to transfer energy through a vacuum
is how we get energy from the sun

4. Chapter 14.2 – Energy Transfer
conductor –
material through which energy can be easily transferred as heat
insulator –
material that transfers energy poorly
conduction and convection transfer energy through particle collisions
the less dense the material, the fewer the collisions, and the less energy transferred
metals conduct energy well, plastics conduct energy poorly

5. Chapter 14.2 – Energy Transfer
specific heat –
amount of energy required to raise the temperature of 1 kg or 1 g of a substance by 1 K
units of J / kg * K
the lower the specific heat, the easier it is to increase the temperature of a substance
the higher the specific heat, the harder it is to increase the temperature of a substance

6. Chapter 14.2 – Energy Transfer
can find the energy needed to heat a substance a certain amount from:
energy needed = specific heat x mass x temperature change
E = c m ΔT
How much energy is needed to increase the temperature of kg of iron from 283 K to 403 K?

7. Chapter 14.2 – Energy Transfer
adding energy as heat to an object will either raise its temperature or change its state
it will not do both at the same time