1 / 68

Today’s special

Stay informed with today's special announcements, including the new seating chart, exam results, and important class policies. Don't forget to check your homework assignments and take notes on the video about Einstein's Big Idea.

canales
Télécharger la présentation

Today’s special

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. Today’s special • Welcome back! New seating chart! • Exam results • Presentation feedback • Late work policy • Attendance policy for this class • Vocab 16 Thermal E & heat-hw check • Video-Einstein’s Big Idea-take notes

  2. Today’s special • Vocab 16 Thermal E & heat-hw check • Video-Einstein’s Big Idea-take notes • Paper due next class • Worktime

  3. Today’s special • Turn in paper on front desk • Notes 16.1 • HW I due next time

  4. Late work • 1. Do your work on time to enhance your learning and to contribute to the academic environment of the class • 2. If you fail to do #1 you can turn in your work late if you attend a full session of homework club • -Full credit potential if you attend the next hw club • -70% potential if you attend within 1 week • -30% potential if you attend within 2 weeks • -10% max if turned in by the retest date for that unit • MSG turns into 0 at that point

  5. Formal academic environment •  Treating pupils with care, fairness and consistency; boosting student-teacher acceptance of diversity; and reducing the emphasis on student competition represent successful methods. It is also important to promote student decision-making, individual and civic responsibility and commitment to the larger school community in order to improve school climate.

  6. In what direction does heat flow spontaneously? Heat is the transfer of thermal energy from one object to another because of a temperature difference. Heat flows spontaneously from hot objects to cold objects. Work and Heat

  7. What is the temperature of an object related to? Temperature is related to the average kinetic energy of the particles in an object due to their random motions through space. Temperature

  8. Temperature Temperature is a measure of how hot or cold an object is compared to a reference point. • On the Celsius scale, the reference points are the freezing and boiling points of water. • On the Kelvin scale, absolute zero is defined as a temperature of 0 kelvins.

  9. What two variables is thermal energy related to? Thermal energy is the total potential and kinetic energy of all the particles in an object. Thermal energy depends on the mass, temperature, and phase (solid, liquid, or gas) of an object. Thermal Energy

  10. Thermal Energy Thermal energy depends on mass and temperature. • The tea is at a higher temperature than the lemonade. • The lemonade has more thermal energy because it has many more particles.

  11. What causes thermal expansion? Thermal expansion is an increase in the volume of a material due to a temperature increase. Thermal expansion occurs when particles of matter move farther apart as temperature increases. Thermal Contraction and Expansion

  12. How is a change in temperature related to specific heat? Specific heat is the amount of heat needed to raise the temperature of one gram of a material by one degree Celsius. The lower a material’s specific heat, the more its temperature rises when a given amount of energy is absorbed by a given mass. Specific Heat

  13. Specific Heat

  14. Specific Heat In this formula, heat (Q) is in joules, mass (m) is in grams, specific heat (c) is in J/g•°C, and the temperature change (Δt) is in degrees Celsius.

  15. Specific Heat Calculating Specific Heat An iron skillet has a mass of 500.0 grams. The specific heat of iron is 0.449 J/g•°C. How much heat must be absorbed to raise the skillet’s temperature by 95.0°C?

  16. Specific Heat Read and Understand What information are you given?

  17. Specific Heat Read and Understand What information are you given?

  18. Specific Heat Plan and Solve What unknown are you trying to calculate? What formula contains the given quantities and the unknown?

  19. Specific Heat Plan and Solve What unknown are you trying to calculate? What formula contains the given quantities and the unknown?

  20. Specific Heat Plan and Solve Replace each variable with its known value.

  21. Specific Heat Plan and Solve Replace each variable with its known value.

  22. Specific Heat Look Back and Check Is your answer reasonable?

  23. Specific Heat Look Back and Check Is your answer reasonable? Round off the data to give a quick estimate. Q = 500 g × 0.5 J/g•°C × 100°C = 25 kJ This is close to 21.4 kJ, so the answer is reasonable.

  24. Specific Heat A calorimeter is used to measure specific heat. A sample is heated and placed in the calorimeter. The temperature change is observed.

  25. Assessment Questions • What is the thermal energy of an object? • the total number of atoms or molecules • the total kinetic energy of the atoms or molecules • the average kinetic energy of the atoms or molecules • the average mechanical energy of the atoms or molecules

  26. Assessment Questions • What is the thermal energy of an object? • the total number of atoms or molecules • the total kinetic energy of the atoms or molecules • the average kinetic energy of the atoms or molecules • the average mechanical energy of the atoms or moleculesANS: B

  27. Assessment Questions • What causes a gas to expand when its temperature is increased? • The number of particles increases as temperature increases. • Each particle expands as its temperature increases, so the total volume increases. • As temperature increases, more electrons leave atoms and move separately. • As gas particles move faster, they overcome some forces of attraction.

  28. Assessment Questions • What causes a gas to expand when its temperature is increased? • The number of particles increases as temperature increases. • Each particle expands as its temperature increases, so the total volume increases. • As temperature increases, more electrons leave atoms and move separately. • As gas particles move faster, they overcome some forces of attraction.ANS: D

  29. Assessment Questions • The specific heat of water is 4.18 J/g•°C. How much heat is required to raise the temperature of 1,000 grams of water by 50°C? • 83.6 J • 83.6 kJ • 209 J • 209 kJ

  30. Assessment Questions • The specific heat of water is 4.18 J/g•°C. How much heat is required to raise the temperature of 1,000 grams of water by 50°C? • 83.6 J • 83.6 kJ • 209 J • 209 kJANS: D

  31. Assessment Questions • What property of matter can be measured using a calorimeter? • temperature • thermal expansion • specific heat • mass

  32. Assessment Questions • What property of matter can be measured using a calorimeter? • temperature • thermal expansion • specific heat • massANS: C

  33. Assessment Questions • Temperature is the transfer of thermal energy from one object to another.TrueFalse

  34. Assessment Questions • Temperature is the transfer of thermal energy from one object to another.TrueFalse ANS: F, Heat

  35. Today’s special • HW Check; Q & A • Lab: Specific heat • Lab due next time!

  36. Today’s special • Turn in lab on front table • Notes II • HW II due next time

  37. Conductors

  38. Insulators

  39. Conduction, convection, radiation

  40. Thermodynamics First Law of Thermodynamics Energy is conserved

  41. Thermodynamics Second Law of Thermodynamics-Entropy

  42. Thermodynamics Third Law of Thermodynamics 0 K cannot be reached

  43. Assessment Questions • What form of energy transfer requires the motion of particles of a fluid? • conduction • convection • radiation • insulation

  44. Assessment Questions • What form of energy transfer requires the motion of particles of a fluid? • conduction • convection • radiation • insulationANS: B

  45. Assessment Questions • What happens in every case in which energy is added to a system? • Temperature increases. • Work is done on the system. • All of the energy can be accounted for as work or heat. • An identical amount of energy is removed from the system.

  46. Assessment Questions • What happens in every case in which energy is added to a system? • Temperature increases. • Work is done on the system. • All of the energy can be accounted for as work or heat. • An identical amount of energy is removed from the system.ANS: C

  47. Assessment Questions • Thermal energy can move from a cooler object to a warmer object when • the warmer object is larger. • the cooler object has more thermal energy. • energy is transferred by radiation. • work is done on the system.

  48. Assessment Questions • Thermal energy can move from a cooler object to a warmer object when • the warmer object is larger. • the cooler object has more thermal energy. • energy is transferred by radiation. • work is done on the system.ANS: D

  49. Assessment Questions • According to the third law of thermodynamics, it is impossible • to cool an object to absolute zero. • transfer thermal energy from a cooler object to a warmer object. • convert energy from one form to another. • account for all of the energy in a system.

  50. Assessment Questions • According to the third law of thermodynamics, it is impossible • to cool an object to absolute zero. • transfer thermal energy from a cooler object to a warmer object. • convert energy from one form to another. • account for all of the energy in a system.ANS: A

More Related