1 / 28

Thermal Energy and Matter

Thermal Energy and Matter. Ch 16.1. Work and Heat. Heat- transfer of thermal energy from 1 object to another due to temperature difference Heat flows from hot objects to cold objects. Temperature. Temperature- measure of how hot or cold an object is compared to a reference point

neil
Download Presentation

Thermal Energy and Matter

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Thermal Energy and Matter Ch 16.1

  2. Work and Heat • Heat- transfer of thermal energy from 1 object to another due to temperature difference • Heat flows from hot objects to cold objects

  3. Temperature • Temperature- measure of how hot or cold an object is compared to a reference point • °C= boiling/freezing point of water • Absolute zero- reference point in K, which is 0K • Temperature relates to the kinetic energy of particles • hot= faster particles • cold= slower particles

  4. Thermal Energy • Depends on: • Mass • Temperature • Phase- solid, liquid, gas of an object

  5. Thermal Contraction and Expansion • Thermal Expansion- increase volume due to temperature increase • Particles move farther apart • Thermometers • Increase temp. = alcohol moves/expands = temperature you read

  6. Specific Heat • Specific Heat- amount of heat needed to raise the temperature of 1g of material by 1°C • The lower the SH, the more the temp. rises when a given amount of energy is absorbed by a given mass

  7. Specific Heat Q = m c ΔT Q- heat absorbed by material, J M- mass, g C- specific heat, J/g°C ΔT- change in temp. °C

  8. Specific Heat Practice • An iron skillet has a mass of 500g. Its specific heat is 0.449 J/g°C. How much heat must be absorbed to raise the temperature by 95C? • Given: • Formula: • Solve:

  9. Math Practice pg 477 • 2. • 4. • 3. • 5.

  10. Measuring Heat Changes • Calorimeter- sealed instrument used to measure changes in thermal energy • Uses principle that hot energy flows to cold, until they equal the same temperature.

  11. Heat and Thermodynamics Ch. 16.2

  12. Conduction • Transfer of thermal energy between 2 touching objects, with no overall transfer of matter • Slower in gases due to particles colliding less often

  13. Conduction Thermal Conductors Thermal Insulators • Conducts thermal energy well • Can be hot or cold • Ex: Cu, Al • Tile vs Wood • Conducts thermal energy poorly • Can be hot or cold • Ex: Air, plastic, wool

  14. Convection • Transfer of thermal energy when particles of a fluid move from 1 place to another • Hot moves to cold • Convection Current- fluid circulates in a loop as it alternatively heats up and cools down • Oven, heaters • Naturally- ocean currents, weather, molten rock

  15. Radiation • Transfer of energy by waves moving through space • Heat lamps • All objects radiate energy- as temperature increases the rate it radiates energy increases

  16. Conduction, Convection or Radiation Heating?

  17. Thermodynamics Thermodynamics 1st Law of Thermodynamics • Study of conversions between thermal energy and other forms of energy • James Joule, 1800’s • Energy is conserved

  18. Thermodynamics 2nd Law of Thermodynamics 4th Law of Thermodynamics • Thermal energy can flow from cold to hot objects ONLY if work is done to the system • Heat engine- device converts heat into work • Waste heat- thermal energy not converted into heat • Absolute zero cannot be reached

  19. Using Heat Ch. 16.3

  20. Heat Engines External Combustion Engine Internal Combustion Engine • Engine that burns fuel outside the engine • Steam engine • Engine that burns fuel inside the engine • Cars

  21. Heating Systems • Central Heating Systems • Heats many rooms from 1 central location • Most use convection to distribute thermal energy

  22. Heating Systems Hot Water Heating Steam Heating • Conduction and radiation using water • Conduction and radiation using steam

  23. Heating Systems Electric Baseboard Heating Forced Air Heating • Conduction and radiation using electrical energy • Convection using fans

  24. Cooling Systems • Heat pumps • Device that reverses the normal flow of thermal energy • Circulates refrigerant through tubing • Refrigerant- fluid that vaporizes and condenses inside the tubing of a heat pump

  25. Cooling Systems Refrigerators Air Conditioners • Transfers thermal energy from the inside to the outside • Cools inside, releases hot air

More Related