Chapter 6: Thermal Energy

1. Chapter 6: Thermal Energy Material on Final Exam

2. Essential Questions How are temperature and kinetic energy related? How do heat and thermal energy differ? What is the effect of having a small specific heat? What happens to a material when it is heated? In what ways can thermal energy be transferred?

3. Thermal Energy, Temperature, and Heat energy kinetic sum potential All matter has _________, or the ability to cause change (do work) Thermal energy is the ______ of the ______________ energy and the _______________ energy of the particles that make up a material

4. Thermal Energy, Temperature, and Heat temperature average kinetic energy added increase • If two substances have the same ________________, then their particles will have the same ________________________________. • Anytime thermal energy is __________to a substance, it causes the substance’s temperature to ____________ increase. • This causes the particles to move faster; thus causing the kinetic energy to increase.

5. Thermal Energy, Temperature, and Heat Greater greater More Higher higher Particles Solids gases Gases • Factors that affect thermal energy • Mass • __________ mass means __________ thermal energy • ________ particles in a more massive object • Temperature • __________ temperature means _________ thermal energy • _________ are moving faster! • Phase (solid, liquid, gas, etc) or an object • _________ have the least, and _________ have the most • _________ have the fastest particles!

6. Thermal Energy, Temperature, and Heat Does the coffee or chocolate milk have more thermal energy? Why? Does the glass or pitcher of lemonade have more thermal energy? Why? Does the frozen or melted ice pop have more thermal energy? Why?

7. Thermal Energy, Temperature, and Heat thermometer average kinetic • How do you know if something is hot? • A ____________________ is used to measure temperature (how hot or cold something is). • Temperature represents the ____________________ energy of the particles that make up a material. • Temperature and thermal energy are not the same!

8. Thermal Energy, Temperature, and Heat • Temperature Scales • ________________ (°F) is most common in the US. • NOT a SI Unit! • ____________ (°C)– Standard SI Unit used. • It is based off the freezing and boiling points of water. • ___________ (K) – Used mostly by scientists. • Absolute zero – The ___________ temperature possible • On the Kelvin scale it is 0 K • Would cause an atom to ______ random ____________. Fahrenheit Celsius Kelvin lowest stop motion 8

10. Thermal Energy, Temperature, and HeatTemperature conversion formulas: Always perform the operation in the parentheses FIRST K = °C+ 273 °C=K-273

11. Thermal Energy, Temperature, and Heat • 335 F = ______ ˚C • 50 F = ______˚ C • 0 F = ______ ˚ C • 100 ˚C = ______ ˚ F • 25˚ C = ______ ˚F • 37˚ C = ______ ˚F

12. Thermal Energy, Temperature, and Heat K = °C+ 273 °C=K-273 • 100 ˚C = ______ K • 25˚ C = ______ K • 37˚ C = ______ K • 335 K = ______ ˚C • 50 K = ______˚ C • 0 K = ______ ˚ C

13. Thermal Energy, Temperature, and Heat • How does heat flow? Demonstration • I will give you two different temperatures of water. They have the same volume • Find their initial temperatures • Mix them together in the Styrofoam cup • KEEP THE LID ON! • After 2 minutes, take the final temperature

14. Thermal Energy, Temperature, and Heat movement warmer cooler not flows equal • Heat is the ___________ of thermal energy from a __________ object to a _____________ object • Temperature and heat are ______ the same! • It _______spontaneously from hot to coldobjects until temperature becomes _______.

15. Writing Prompt #1 (of 3) • Write the answer on your green sheet. • How are thermal energy, heat, and temperature related! FULL SENTENCES FOR FULL CREDIT!

16. Thermal Energy Transfers Radiation Conduction Convection • There are three different ways that thermal energy (heat) can transfer from substance to another • _______________ • ________________ • ________________

17. Thermal Energy Transfers waves not matter sun fire • Radiation is the transfer of energy from one material to another by electromagnetic _________ moving through space. • Does ______ need ________to transfer through, but can travel through all states of matter • Examples: ______, heat lamps, ________, hot car

18. Thermal Energy Transfers Radiation heats gases trapped ______________ passes through the atmosphere and _________ up the _________ that get ____________ in the atmosphere. Some scientists are concerned that high levels of greenhouse gases in the atmosphere may trap too much energy and make Earth too warm.

19. Thermal Energy Transfers collisions particles • Conduction is the transfer of thermal energy between materials by the ______________ of ____________. • Within one substance • Between substances in contact • EX: Newton’s cradle, melting ice • Solids v. liquids v. gases

20. Thermal Energy Transfers • Thermal _______________ are materials through which thermal energy flows ___________ • ____________ • Tile • Thermal __________________are materials through which thermal energy flows __________ • ______ • Wood • Wool • ______________________ insulators conductors poorly easily Air Metal Styrofoam/plastic

21. Thermal Energy Transfers • Specific Heatis the _____________________ required to _________ the ________________ of one kilogram of a material by one degree Celsius. • Formula – • Heat added = Mass X specific heat X change in temperature thermal energy raise temperature Q = mcΔT

22. Thermal Energy Transfers Joules J kg J/(kg•°C) °C • Heat – unit of measurement = ___________ • Q = heat (___) • m = mass (____) • c = specific heat (_________) • ΔT =change in temp (_________)

23. SAMPLE 1: An iron skillet has a mass of 0.5 kilograms. The specific heat of iron is 449J/kg·°C. How much heat must be absorbed to raise the skillet's temperature by 95.0°C? • EXAMPLE 1: YOU TRY • How much heat is needed to raise the temperature of 0.100 kg of water by 85.0°C? Water has a specific heat of 4184 J/kg°C. Thermal Energy Transfers Solving for Q

24. SAMPLE 2:In setting up an aquarium, the heater transfers 1,200,000 J of heat to 75 kg of water. What is the increase in the water's temperature? Water has a specific heat of 4184 J/kg°C. • EXAMPLE 2: YOU TRY • To release a diamond from its setting, a jeweler heats a 0.01kg silver ring by adding 23.5 J of heat. How much does the temperature of the silver increase? The specific heat of silver is 240 J/kg°C. Thermal Energy Transfers Solving for ΔT

25. SAMPLE 3:A piece of plastic requires 6900J of heat to raise the temperature from 25 to 55°C. If the specific heat of plastic is 1840 J/kg˚C, what is the mass? • EXAMPLE 3: YOU TRY • What mass of water (specific heat 4184 J/kg°C) will change its temperature by 3.0°C when 525,000 J of heat is added to it? Thermal Energy Transfers Solving for m

26. Writing Prompt #2 (of 3) • Write the answer on your green sheet. • What mistakes do you think you will make on this type of word problem? Give two different types, and explain how you can prevent them FULL SENTENCES FOR FULL CREDIT!

27. Thermal Energy Transfers heat energy lost gained other object How do you measure heat changes? Calorimeters - A calorimeter is a device that measures ______. When one object transfers thermal energy to another object, the ___________________ by one object is ___________ by the _________________. The sample to be tested is heated and placed in the container. The lid is put on and the temperature change is observed.

28. Thermal Energy Transfers You can use this to help with the lab!!! Lab Data—example Mass of metal object: 0.087 kilograms Volume of water: 50 ml Remember, water has a density of 1g/ml Initial water temperature: 21C Final water temperature: 27 C Specific heat of water: 4.18 J/kg°C

29. Thermal Energy Transfers • To find the specific heat of the metal… • Find the heat gained by the water using Q = mcΔt • The heat gained by the water = heat lost by metal (think of the law of conservation of energy.

30. Thermal Energy Transfers • Solve for the specific heat of the metal using Q = mcΔt • If the metal is supposed to be Antimony (with a specific heat of 207 J/kg°C), find the percent error • % error = |what you got – actual specific heat| x 100% actual specific heat

31. Thermal Energy Transfers changes volume temperature temperature decreases decrease volume/pressure • _________ contract the _________, followed by liquids then solids. Gases most Matter ___________ its ___________ with a change in _____________ . Thermal contraction – as _______________ _______________, particles move slower therefore ___________________________ _______________. EX: balloons, potholes

32. Thermal Energy Transfers volume/pressure increases temperature increase • Matter changes its volume with a change in heat. • Thermal expansion is when the object ________________ its _____________________ due to a ________________________. • Gases expand the most, followed by liquids then solids. • Ex. Thermometers, roads, balloons.

33. Thermal Energy Transfers • More examples • As the temperature goes up, the volume goes up • Bridges/sidewalks- joints allow for expansion • Hot air balloons-air is heated, it expands, less dense = balloon rises • Pyrex- heats more evenly and expands less so it doesn’t shatter

34. Convection transfer part movement of particles another loop Convection is the __________ of thermal energy of the ______________________ from one __________ of a material to _____________. Convection currents happen when a fluid circulates in a ______ as it heats and cools.

35. Writing Prompt #3 (of 3) • Write the answer on your green sheet. • Summarize the picture explaining why each example is conduction, convection, and radiation. Be sure to explain why the poker is a thermal conductor and the glove is a thermal insulator. FULL SENTENCES FOR FULL CREDIT!