1. Temperature
• The measure of how hot or cold
something is
• Specifically – how fast the particles are
moving, average kinetic energy
• Matter is made of atoms that are always
moving, or they have kinetic energy
• The more kinetic energy, the higher the
temperature

2. • Measuring temperature measures the average
kinetic energy of an object
• Temperature is measured with a thermometer
• Thermal expansion – increase in the size of a
substance in response to an increase in temp
(as temp increases, particles move faster,
spreading out)
• Because of thermal expansion, all materials can
expand and shrink when temperature changes

3. • Mercury and alcohol are used in
thermometers because they increase in
size (expand) by constant amounts, stay
liquid at high and low temperatures
• Fahrenheit
– Boiling pt 212°
– Freezing pt 32°

4. • Celsius
– Boiling pt 100°
– Freezing pt 0°
• Kelvin
– Boiling pt 373
– Freezing pt 273
• Lowest temp on Kelvin scale is 0 or
absolute zero (-459°F), the temperature at
which all molecules stop moving

5. • Heat – the energy transferred between
objects that are at different temperatures
• Thermal energy – kinetic energy of a
substances atoms
• Thermal energy is transferred from areas
warmer to areas that are cooler until both
are equal

6. Conduction – the transfer of energy, as
heat, through a material (touching)

7. Conductors and Insulators
• Materials that transfer heat are called
thermal conductors
• Materials that do not transfer heat are
called thermal insulators
• Examples:
– Insulators: feathers, blankets, plastics
– Conductors: metals
• Thermal conductivity is the rate at which a
material conducts heat

8. Radiation – the transfer of energy
as electromagnetic waves (sun)

9. • Radiant energy from the sun heats earth
• Examples:
– Fire
– Radiator
– Electric Oven
– Electric stove

10. Convection is the transfer of thermal energy
by the circulation or movement of a liquid or
a gas

11. • Energy transfer can not be measured
directly, instead it must be calculated
• Heat = joules (J)
• Specific heat = (J/Kg x ° C)
• Mass = Kg
• Temperature = ° C
• Formula to calculate heat:
J = (J/Kg x ° C) x Kg x ° C

12. Review