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Chapter Introduction Lesson 1 Thermal Energy, Temperature, and Heat Lesson 2 Thermal Energy Transfers Lesson 3 Using Thermal Energy Chapter Wrap-Up. Chapter Menu. Do you agree or disagree?. 1. Temperature is the same as thermal energy.

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  1. Chapter Introduction Lesson 1 Thermal Energy, Temperature, and Heat Lesson 2 Thermal Energy Transfers Lesson 3Using Thermal Energy Chapter Wrap-Up Chapter Menu

  2. Do you agree or disagree? 1.Temperature is the same as thermal energy. • Heat is the movement of thermal energy from a hotter object to a cooler object. • It takes a large amount of energy to significantly change the temperature of an object with a low specific heat. • The thermal energy of an object can never be increased or decreased. Chapter Introduction

  3. Thermal Energy, Temperature, and Heat • How are temperature and kinetic energy related? • How do heat and thermal energy differ? Lesson 1 Reading Guide - KC

  4. Thermal Energy, Temperature, and Heat - in your own words come up with a definition for each of the words below • thermal energy • temperature • heat Lesson 1 Reading Guide - Vocab

  5. Kinetic and Potential Energy • Potential energy is stored energy due to the interaction between two objects. • The potential energy plus the kinetic energy of an object is the mechanical energy of the object. Lesson 1-1

  6. What is thermal energy? • Every solid, liquid, and gas is made up of trillions of tiny particles that are constantly moving. • Because particles are in motion, they have kinetic energy. • The faster particles move, the more kinetic energy they have. Lesson 1-2

  7. What is thermal energy?(cont.) • The greater the average distance between particles, the greater the potential energy of the particles. • Thermal energy is the sum of the kinetic energy and the potential energy of the particles that make up a material. Lesson 1-2

  8. The potential energy of the soccer ball depends on the distance between the ball and Earth. The potential energy of the particles of matter depends on their distance from one another. Lesson 1-2

  9. What is thermal energy?(cont.) • Mechanical energy describes the energy of one object. • Thermal energy describes the energy of the particles that make up a solid, liquid, or gas. Lesson 1-2

  10. What is temperature? • Scientists define temperature in terms of kinetic energy. • Temperature represents the average kinetic energy of the particles that make up a material. Lesson 1-3

  11. What is temperature?(cont.) • The greater the average kinetic energy of particles, the greater the temperature. • The particles in warmer air move at a greater average speed than the particles in colder air. Lesson 1-3

  12. What is temperature?(cont.) • Temperature and thermal energy are related, but they are not the same. • The particles that make up liquid and solid water have different potential energies and, therefore, different thermal energies. Lesson 1-3

  13. What is temperature?(cont.) • Thermometers are used to measure temperature. • Common temperature scales are Celsius (°C), Kelvin (K), and Fahrenheit (°F). Lesson 1-3

  14. What is heat? • The movement of thermal energy from a warmer object to a cooler object is called heat. • All objects have thermal energy; however, you heat something when thermal energy transfers from one object to another. • The rate at which heating occurs depends on the difference in temperatures between the objects. Lesson 1-4

  15. The greater the distance between two particles or two objects, the greater the potential energy. • Heat is the movement of thermal energy from a warmer object to a cooler object. Lesson 1 - VS

  16. When thermal energy moves between a material and its environment, the material’s temperature changes. Lesson 1 - VS

  17. Because particles are in motion, what type of energy do they have? A. thermal energy B. potential energy C. mechanical energy D. kinetic energy Lesson 1 – LR1

  18. Particles that make up liquid and solid water have different potential energies, and therefore also have which of the following? A. different thermal energies B. different temperatures C. different kinetic energies D. the same thermal energy Lesson 1 – LR2

  19. Which term refers to the average kinetic energy of the particles that make up a material? A. heat B. temperature C. potential energy D. thermal energy Lesson 1 – LR3

  20. 1. Temperature is the same as thermal energy. 2. Heat is the movement of thermal energy from a hotter object to a cooler object. Do you agree or disagree? Lesson 1 - Now

  21. Thermal Energy Transfers • 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? Lesson 2 Reading Guide - KC

  22. Thermal Energy Transfers • thermal expansion • thermal contraction • convection • convection current • radiation • conduction • thermal conductor • thermal insulator • specific heat Lesson 2 Reading Guide - Vocab

  23. How is thermal energy transferred? • Thermal energy is transferred in three ways. • by radiation • by conduction • by convection Lesson 2-1

  24. Radiation • The transfer of thermal energy from one material to another by electromagnetic waves is called radiation. • Radiation is the only way thermal energy can travel from the Sun to Earth, because space is a vacuum. • Radiation also transfers thermal energy through solids, liquids, and gases. Lesson 2-2

  25. Conduction • When particles with different kinetic energies collide, the particles with higher kinetic energy transfer energy to particles with lower kinetic energy. • The transfer of thermal energy between materials by the collisions of particles is called conduction. • Conduction continues until the thermal energy of all particles in contact is equal. Lesson 2-3

  26. Conduction (cont.) • The hot air transfers thermal energy to, or heats, the cool lemonade by conduction. • Eventually the kinetic thermal energy and temperature of the air and the lemonade will be equal. Lesson 2-3

  27. Conduction (cont.) • A thermal conductor is a material through which thermal energy flows easily. • A thermal insulator is a material through which thermal energy does not flow easily. Lesson 2-3

  28. Conduction (cont.) • The amount of thermal energy required to increase the temperature of 1 kg of a material by 1°C is called specific heat. • Water’s high specific heat helps prevent your body from overheating. • Changing the temperature of a material with a low specific heat is easier than to change the temperature of a material with a high specific heat. Lesson 2-3

  29. In a hot car, the temperature of thermal conductors, such as the safety-belt buckles, increases more quickly than the temperature of thermal insulators, such as the seat material. Lesson 2-3

  30. The metric unit for measuring heat is the joule. • This is the same joule used to measure all forms of energy, not just heat. Units of heat and thermal energy

  31. Thermal energy is often measured in calories. • One calorie is the amount of energy it takes to raise the temperature of one milliliter of water by one degree Celsius. Heat and thermal energy

  32. The specific heat is a property of a substance that tells us how much heat is needed to raise the temperature of one kilogram of a material by one degree Celsius. Knowing the specific heat of a material tells you how quickly the temperature will change as it gains or loses energy. Specific Heat

  33. Temperature measures the average kinetic energy per particle. • Energy that is divided between fewer particles means more energy per particle, and therefore more temperature change. • In general, materials made up of heavy atoms or molecules have low specific heat compared with materials made up of lighter ones. Why is specific heat different for different materials?

  34. Conduction (cont.) What does it mean if a material has a low specific heat? Lesson 2-3

  35. The heat equation

  36. How much heat is needed to raise the temperature of a 250-liter hot tub from 20°C to 40°C? Solving Problems

  37. Looking for: • …amount of heat in joules • Given: • V = 250 L, 1 L of water = 1 kg • Temp changes from 20°C to 40°C • Table specific heat water = 4, 184 J/kg°C • Relationships: • E = mCp(T2 – T1) • Solution: • E = (250L × 1kg/L) × 4,184 J/kg°C (40°C - 20°C) = 20,920,000 J • Sig. fig./Sci. not. 20,920,000 J = 2.1 x 107 J Solving Problems

  38. Thermal Expansion and Contraction • Thermal contraction is a decrease in a material’s volume when its temperature decreases. • Thermal expansion is an increase in a material’s volume when its temperature increases. • Thermal expansion and contraction are most noticeable in gases, less noticeable in liquids, and the least noticeable in solids. Lesson 2-4

  39. Thermal Expansion and Contraction (cont.) What happens to the volume of a gas when it is heated? Lesson 2-4

  40. Convection • Convection is the transfer of thermal energy by the movement of particles from one part of a material to another. • Convection only occurs in fluids. convection from Greek convectionem, means “the act of carrying” Lesson 2-5

  41. This cycle of cooler water sinking and forcing warmer water upward is an example of convection. Lesson 2-5

  42. Convection(cont.) What are the three processes that transfer thermal energy? Lesson 2-5

  43. Convection(cont.) • The movement of fluids in a cycle because of convection is a convection current. • Convection currents circulate the water in Earth’s oceans and other bodies of water. Lesson 2-5

  44. Convection Currents in Earth’s Atmosphere Lesson 2-5

  45. When a material has a low specific heat, transferring a small amount of energy to the material increases its temperature significantly. Lesson 2 - VS

  46. Thermal energy can be transferred through radiation, conduction, or convection. Lesson 2 - VS

  47. When a material is heated, the thermal energy of the material increases and the material expands. Lesson 2 - VS

  48. Which term refers to a material through which thermal energy flows easily? A. convection current B. specific heat C. thermal conductor D. thermal insulator Lesson 2 – LR1

  49. Which describes an increase in a material’s volume when its temperature increases? A. conduction B. thermal expansion C. thermal conductor D. thermal contraction Lesson 2 – LR2

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