Thermal Energy & Heat 1.Temperature – The measure of the average kinetic energy of the particles that make up a substance. 2.Temperature Scales – Fahrenheit, Celsius and Kelvin 3.Fahrenheit ( 0 F) – The most common temperature scale in the U.S. – 32 0 F water freezes and F water boils – 4.Celsius Scale ( 0 C) – The most common temperature scale in the World. – 0 0 C water freezes and C water boils -

Thermal Energy & Heat 5. Kelvin Scale (K) – The temperature scale used most commonly by physical scientists. 273 K = Water Freezing 373 K = Water Boiling Converting Kelvin to degrees Celsius 273 K – 273 = 0 0 C  Freezing H 2 O 373 K – 273 = C  Boiling H 2 O

Thermal Energy & Heat 6. Absolute Zero – Zero K [0 K] – The lowest temperature possible. At this temperature no more energy can be removed from matter. 7. Thermal Energy – The total energy of all the particles in a substance. a. Temperature b. Number of Particles c. Arrangement 2 L of Hot cocoa vs 0.15 L of Hot Cocoa 75 0 C75 0 C

Thermal Energy & Heat 8. Heat Movement – Thermal Energy (Heat) always moves from a warmer substance to a cooler substance. 9. How is heat moved or transferred? a. Conduction b. Convection c. Radiation 10. Conduction – Heat is transferred from one particle of matter to another without the movement of matter itself. Ex. A metal spoon in a hot cup of coffee

Thermal Energy & Heat 11. Convection - Heat is moved by the movement of currents within a liquid or gas (a fluid). The hot fluid is less dense and rises. The cold fluid is more dense and sinks.

Thermal Energy & Heat 12. Radiation – The transfer of heat energy by electromagnetic waves. Radiation does not require matter for the transfer to occur. Sunlight can travel through empty space. Ex. The Sun 13. Heat only moves one way! - Heat always flows from warm to cold.

Thermal Energy & Heat 14. Insulators – A material that does not conduct heat well. Ex. Fiber Glass, also air can be an insulator 15. Specific Heat – The amount of energy required to raise the temperature of 1 kg of a substance 1 Kelvin. 16. Calculating Specific Heat – Mass (kg) x Specific Heat (J/kg. K) x Change in Temp. (K)

Thermal Energy & Heat States of Matter 17. Solids – Particles packed together in relatively fixed positions. Solids have fixed shapes & volumes. 18. Liquids – Particles of a liquid are not held together as tightly as particles of a solid. Particles of a liquid move around. Liquids do not have a fixed shape, but they do have a fixed volume. 19. Gases – Particles moving so fast they can not stay together. No fixed shape or volume!

Thermal Energy & Heat 20. Changes of State – The physical change from one state of matter to another. Changes in state are based on thermal energy changes. Gas  Liquid  Solid Thermal energy decreases. 21. Melting & Melting Point – Solid  Liquid The solid absorbs heat & particles move faster. The temp. at which this happens is called the melting point.

Thermal Energy & Heat 22. Freezing & Freezing Point – Liquid  Solid The liquid loses its thermal (heat) energy and the liquid’s particles slow down & the liquid becomes a solid. The temp. at which this happens is called the freezing point. 23. Vaporization – Liquid  Gas – (Evaporation & Boiling) – Particles in the liquid absorb thermal (heat) energy and start moving faster until they leave the liquid and become a gas. Boiling point is the temp. at which the liquid becomes a gas.

Thermal Energy & Heat 24. Condensation – Gas  Liquid – Gas particles lose thermal (heat) energy & slow (cool) down into a liquid. 25. Thermal Expansion – As the thermal energy of a substance increases its particles spread out & the substance expands. Ex. Thermometers – Alcohol or Mercury Teeth – Fillings must expand and contract

Thermal Energy & Heat 26. Thermostats – Heat regulating devices that use thermal expansion. They contain bimetallic strips. 27. Heat Engines – Convert thermal energy to mechanical energy. Heat engines usually use combustion. 28. External Combustion Engines – The fuel is burned outside the engine. Ex. Steam Engine 29. Internal Combustion Engine – The fuel is burned in cylinders inside the engine. Ex.’s Gasoline & Diesel Engines

Thermal Energy & Heat 30. Refrigerators – Use a motor to transfer thermal energy from a cool area to a warm area. They use an electric motor & a compressor.

Thermal Energy & Heat 31. Graphing Changes of State (Water) –