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Temperature Measure of the average kinetic energy of the
particles in an object Same average kinetic energy = equal temperature
Absolute zero The lowest temperature on the Kelvin
scale 0 K (about -273.16°C) Temperature where all molecular motion
stops Not possible to reach it
Converting temperaturesCelsius to Fahrenheit°F = (9/5 x °C) + 32
Fahrenheit to Celsius°C = 5/9 x (°F – 32)
Celsius to KelvinK = °C + 273
Kelvin to Celsius°C = K – 273
Freezing point of water32° F0° C
273 K
Thermal energy The total kinetic energy of the particles
that make up a substance Measured in joules (J)
Thermal conduction The transfer of thermal energy from one
substance to another through a material or direct contact
Thermal conductors A material through which energy can be
transferred as heat Example: metals
Curling iron Cookie sheet Iron skillet Copper pipe Stove coil
Thermal insulators A material that reduces or prevents the
transfer of heat Examples
Flannel shirt Oven mitt Plastic spatula Fiberglass insulation Ceramic bowl
Convection Transfer of thermal energy by the circulation or
movement of a liquid or a gas Convection causes the repeated rising and
sinking of water during boiling Wind is a result of earth heating by sun
States of matter The physical forms in which a substance
can exist Particles move at different speeds The “state” of a substance depends on
Particle speed (kinetic energy) Attraction between particles (potential
energy) Pressure around particles
Change of state A change of a substance from one state
of matter to another Physical change only
Just affects physical properties but NOT the identity of the substance (i.e. water is still water whether it is a solid, liquid, or a gas)
Changes of state
• Freezing: liquid to solid• Melting: solid to liquid• Boiling: liquid to gas• Condensing: gas to liquid
Insulation Material that reduces the transfer of
thermal energy (i.e. less heat passes into or out of)
Used in walls, ceilings, and floors Helps houses stay warm in the winter Helps houses stay cool in the summer
Heat engine Machine that uses heat to do work Fuel combines with oxygen (O2 ) in a
chemical change that releases thermal energy