Black Body Radiation

• What is blackbody radiation?

  Radiation emitted by a perfect black body
• How does the temperature of an object relate to radiation?

  It depends on absorbed and emitted radiation
• What surfaces are the best absorbers of infrared radiation?

  Matte black surfaces
• What happens to infrared radiation emitted by hotter objects?

  They emit more than cooler objects
• How does the wavelength of radiation change with temperature?

  Hotter objects emit shorter wavelength radiation
• What is a perfect black body in terms of radiation?

  It absorbs all incident radiation
• What does a perfect black body also do well besides absorbing radiation?

  It emits radiation well
• What happens to an object warmer than its surroundings?

  It emits more radiation than it absorbs
• What happens to a cooler object in relation to its surroundings?

  It absorbs more radiation than it emits
• What occurs when an object is at a constant temperature?

  It absorbs and emits radiation at the same rate
• How does the Earth gain or lose energy?

  Through absorbing or emitting radiation
• What type of radiation does the Sun emit?

  Short wavelength radiation
• What happens to some of the Sun's radiation when it reaches Earth?

  Some is reflected by clouds
• What happens to the Earth's temperature when it absorbs radiation?

  It causes the temperature to increase
• What type of radiation does the Earth emit back into space?

  Infrared radiation
• What effect do greenhouse gases have on infrared radiation?

  They trap some energy in the atmosphere
• How does human activity affect greenhouse gas levels?

  It increases the levels of greenhouse gases
• What is the effect of cloud cover on energy radiated from the Earth?

  Clouds can reflect infrared back to Earth
• Why are cloudy nights warmer than clear nights?

  Clouds reflect infrared back to Earth
• Where can students find questions on radiation emission and absorption?

  In the vision workbook