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Bell Ringer

Bell Ringer. Name: 2/25/2009 What’s your favorite song and artist? Response. Newton’s Cooling Lab. Homework Answers. A room temperature metal is a better conductor than the room temperature paper, wood or cloth. A conductor transfers heat quickly and an insulator transfers heat slowly

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Bell Ringer

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  1. Bell Ringer Name: 2/25/2009 What’s your favorite song and artist? Response

  2. Newton’s Cooling Lab

  3. Homework Answers • A room temperature metal is a better conductor than the room temperature paper, wood or cloth. • A conductor transfers heat quickly and an insulator transfers heat slowly • Materials such as wood, fur, feathers and snow are not tightly packed and air can occupy the empty spaces and air is a good insulator. • Costal winds change direction because land is warmer than the water during the day and warm air rises allowing dense air from water to slip underneath. At night the process reverses and the wind direction changes.

  4. Homework Answers • Gas is compressed and temperature increases; Gas expands and temperature cools (molecules move further apart and collide less frequently) • Higher temperatures produce shorter wavelengths (sun and UV), cooler temperatures produce longer wavelengths (fire and infrared) • A good absorber of radiant energy appears black because it absorbs visible radiant energy and so appear black in color. • Eye pupils appear black because they are almost perfect absorbers of visible light and reflect very little.

  5. Homework Answers • The red hot poker in a hot fire will have the lower rate of cooling than the red hot poker in a cool room because the temperature difference is smaller. • Terrestrial radiation is the radiant energy naturally emitted by Earth. • The sun in a hot object and produces short waves, Earth’s temperature is cooler than the sun so it produces longer waves. • A. The greenhouse effect lets energy through in one direction, only the short waves pass back out. • B. Earth; The waves must pass through both the atmosphere and glass before they get to the greenhouse.

  6. Homework Answers Extra credit: • Coal dust is a good absorber and then emitter of radiant energy and melts the snow.

  7. Test Review #1 • Explain why white clothing helps keep us cool, whereas black clothing helps to warm us. Which is the better reflector? Which is the better absorber?

  8. Test Review #1 • Explain why white clothing helps keep us cool, whereas black clothing helps to warm us. Which is the better reflector? Which is the better absorber? • White clothing reflects all colors of light and absorbs very little of the light. It also reflects infrared radiation. Since the energy of the infrared and light radiation is reflected away, we are not warmed by it. Black clothing absorbs almost all of the radiation that falls on it, infrared as well as light. The energy absorbed by black clothing is felt as heat and warms us.

  9. Test Review #2 • Write a few sentences about the differences between conduction and convection. Give examples of each.

  10. Test Review #2 • Write a few sentences about the differences between conduction and convection. Give examples of each. • Heat conduction occurs when a warmer electron, atom, or molecule bumps into a cooler electron, atom, or molecule, transferring kinetic energy. This particle, in turn, bumps into the next particle and in effect transfers kinetic energy even further, and so on. Convection occurs when the warmer atom or molecule actually travels to another place in space. Whereas conduction occurs primarily in solids, convection occurs in fluids -- liquids or gases. When cold water is poured into hot soup, the water soon spreads by convection to all parts of the mixture. When a spoon is placed in the hot soup, the whole spoon becomes hot by conduction.

  11. Test Review #3 • Explain why putting a dented Ping-Pong ball in a pot of boiling water will help remove the dent.

  12. Test Review #3 • Explain why putting a dented Ping-Pong ball in a pot of boiling water will help remove the dent. • As air inside the ball is heated, it expands and pushes outward on the dented ball. Often a dented Ping-Pong ball can be put back in a rounded shape this way.

  13. Test Review #4 • The rate of cooling of an object is proportional to the temperature difference between the object and its surroundings. • True or False

  14. Test Review #4 • The rate of cooling of an object is proportional to the temperature difference between the object and its surroundings. • True or False • True

  15. Test Review #5 • All objects with any temperature at all radiate energy. • True or False

  16. Test Review #5 • All objects with any temperature at all radiate energy. • True or False • T

  17. Test Review #6 • The absorption effect is the name given to the process whereby long-wavelength radiation enters a house through the windows, is absorbed and reradiated by objects in the house, and is unable to be retransmitted through the windows. • True or False

  18. Test Review #6 • The absorption effect is the name given to the process whereby long-wavelength radiation enters a house through the windows, is absorbed and reradiated by objects in the house, and is unable to be retransmitted through the windows. • True or False • F

  19. Test Review #7 • Heat transfer by means of atoms moving from place to place is conduction. • True or False

  20. Test Review #7 • Heat transfer by means of atoms moving from place to place is conduction. • True or False • F

  21. Test Review #8 • A good emitter of heat is also a good reflector of heat. • True or False

  22. Test Review #8 • A good emitter of heat is also a good reflector of heat. • True or False • F

  23. Test Review #9 • Materials that are poor heat conductors are insulators. • True or False

  24. Test Review #9 • Materials that are poor heat conductors are insulators. • True or False • T

  25. Test Review #11 • Winds and weather patterns are good examples of radiation currents. • True or False

  26. Test Review #11 • Winds and weather patterns are good examples of radiation currents. • True or False • F

  27. Test Review #12 • A good reflector of heat is a poor absorber of heat. • True or False

  28. Test Review #12 • A good reflector of heat is a poor absorber of heat. • True or False • T

  29. Test Review #13 • Heat that is transferred to us from the sun is transferred by radiation. • True or False

  30. Test Review #13 • Heat that is transferred to us from the sun is transferred by radiation. • True or False • T

  31. Test Review #13 • Heat transfer by means of electrons colliding with other electrons in a metal is convection. • True or False

  32. Test Review #13 • Heat transfer by means of electrons colliding with other electrons in a metal is convection. • True or False • F

  33. Test Review #14 • The rate of cooling of an object is proportional to the temperature difference between the object and its surroundings. • True or False

  34. Test Review #14 • The rate of cooling of an object is proportional to the temperature difference between the object and its surroundings. • True or False • T

  35. Test Review #15 • All objects with any temperature at all radiate energy. • True or False

  36. Test Review #15 • All objects with any temperature at all radiate energy. • True or False • T

  37. Test Review #16 • Heat transfer by means of atoms moving from place to place is conduction. • True or False

  38. Test Review #16 • Heat transfer by means of atoms moving from place to place is conduction. • True or False • F

  39. Test Review #17 • Gases don't expand very much when heated. • True or False

  40. Test Review #17 • Gases don't expand very much when heated. • True or False • F

  41. Test Review #18 • A temperature scale that has 100 degrees between the boiling point and the freezing point of water is the Fahrenheit scale. • True or False

  42. Test Review #18 • A temperature scale that has 100 degrees between the boiling point and the freezing point of water is the Fahrenheit scale. • True or False • F

  43. Test Review #19 • Water contracts when heated from 0 degrees C to 4 degrees C. • True or False

  44. Test Review #19 • Water contracts when heated from 0 degrees C to 4 degrees C. • True or False • T

  45. Test Review #20 • Heat is the energy that transfers from one object to another because of a temperature difference. • True or False

  46. Test Review #20 • Heat is the energy that transfers from one object to another because of a temperature difference. • True or False • T

  47. Test Review #21 • The amount of heat required to change the temperature of a unit mass of a substance by 1 degree is its specific heat capacity. • True or False

  48. Test Review #21 • The amount of heat required to change the temperature of a unit mass of a substance by 1 degree is its specific heat capacity. • True or False • T

  49. Test Review #22 • The total of all energies in a substance is its temperature. • True or False

  50. Test Review #22 • The total of all energies in a substance is its temperature. • True or False • F

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