black body radiation

• What should you be able to describe by the end of this video?

  What's meant by blackbody radiation
• What relationship should you understand regarding an object by the end of the video?

  Temperature depends on absorbed and emitted radiation
• For whom is this video intended?

  Triple physics students only
• Which surfaces are the best absorbers and emitters of infrared radiation?

  Matte black surfaces
• What do all objects do, regardless of temperature, concerning infrared radiation?

  Emit and absorb infrared radiation
• How does the infrared radiation emitted by a hotter object compare to a cooler one?

  Hotter objects emit more in a given time
• On what two factors does the radiation from an object depend?

  Wavelength and intensity
• What type of wavelength radiation does a very hot object emit compared to a cooler object?

  Shorter wavelength radiation
• Why do very hot objects produce visible light?

  They emit more short wavelength radiation
• How does the intensity of radiation change at higher temperatures?

  It increases
• What happens to radiation incident on a perfect black body?

  It absorbs all of it
• What kind of emitter is a perfect black body?

  The best possible emitter
• What happens to an object warmer than its surroundings?

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

  It absorbs more radiation than it emits
• What happens to the temperature of an object warmer than its surroundings?

  Its temperature will decrease
• What happens to the temperature of an object cooler than its surroundings?

  Its temperature will increase
• What happens to an object at a constant temperature?

  It absorbs at the same rate it emits
• What are the only ways the Earth can gain or lose energy?

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

  Short wavelength radiation
• What can reflect radiation traveling to earth?

  Clouds
• What happens when radiation is absorbed by the surface of the Earth?

  The Earth's temperature increases
• What type of radiation does the Earth emit back into space?

  Infrared radiation
• What traps some of the energy of the infrared radiation emitted by Earth?

  Greenhouse gases
• How does increased greenhouse gases affect heat energy and space?

  More heat is trapped, less radiated
• How does cloud cover affect nighttime temperatures?

  Cloudy nights tend to be warmer
• How do clouds keep nights warmer?

  They reflect infrared back to Earth
• Where can you find plenty of questions on how radiation is emitted and absorbed?

  In the revision workbook
• What is the effect of human activity on greenhouse gases?

  It is increasing the levels
• What is one factor that affects how much energy is radiated from the earth?

  The amount of cloud cover
• What science courses include the unit one physics series based on this video?

  Core science, double science, and individual physics
• What type of radiation will this video discuss?

  Infrared radiation
• What common devices might use infrared sensors?

  Mobile phones and TV remotes
• What word is used as a fancy word for 'gives out'?

  Emits
• What determines the amount of infrared radiation an object emits?

  Its temperature
• How does the temperature of an object affect the infrared radiation it emits?

  Hotter objects emit more infrared radiation
• Where is infrared radiation located on the electromagnetic spectrum, relative to visible light?

  Next to red light
• What happens when white light is shot at a prism?

  It splits into its component colors
• Besides visible light, what other types of radiation are present in white light?

  Infrared and ultraviolet
• Why can't we see infrared and ultraviolet light?

  Our eyes only detect visible light
• Where is ultraviolet radiation located relative to violet on the electromagnetic spectrum?

  Next to the violet