Plants and Radiation
By: Caitlin

  • Electromagnetic Spectrum
    • different kinds of light have different frequencies and wavelengths
      • frequencies are the speed of the radiation in cycles per second
      • wavelengths are the measure of the waves from one crest to another
      • both of these contain such high numbers that the can only be expressed in powers of ten
    • there are many different kinds of radiation
      • radio waves
        • same kind of waves emitted from radio stations for radios to catch
        • also emitted from stars and gases in space
      • infrared
        • radiation that our skin emits
        • this is why we can be seen through night vision goggles
      • ultraviolet
        • radiation emitted from the Sun
        • burns our skin
      • x-rays
        • radiation doctors use to see through our skin
      • gamma rays
        • very high frequency with low wavelength
        • emitted from radioactive materials
    • our eyes can only see visible light
      • visible light is a type of radiation






  • Visible Light
    • made up of six different colors
      • violet, blue, green, yellow, orange, red
      • also ultraviolet light
    • different colors have different wavelengths and frequencies
      • red has the longest wavelength
      • violet has the shortest wavelength
    • when put togethor, they make a white light
      • colors can be split up using a prism


p2g2scan_of_electromagnetic_spectrum.jpg



  • Plants
    • contain a pigment called chlorophyll
    • chlorophyll only uses certain wavelengths of visible light
      • red: long wavelength
      • blue: short wavelength
    • green is reflected off of the chlorophyll
    • this is what makes many plants appear green

  • How do plants react to ultraviolet radiation?
    • some react different than others
    • they adapt to their environment
      • plants that originate from places with high UV levels (like around the equator) can learn to tolerate it
      • plants that originate from places with low UV levels (mid-latitude areas) do not react as well because they never learn to react
    • some plants change their physiology to adapt to the UV light and learn to thrive in it


  • Greenhouses
    • glass greenhouses
      • glass allows solar radiation to pass through
      • this is used by the plants inside
      • thermal infrared radiation is emitted from the plants
        • glass doesn't allow this to pass throughto the outside
        • this keeps the temperature higher in the inside of the greenhouses than the outside
    • Why does the greenhouse get so hot?
      • the soil is heated inside the greenhouse
      • this heat is conducted from the earth to the air
      • the warm air rises, allowing for the cooler, denser air around it to take its place
      • because the air is confined to the greenhouse, this allows the greenhouse to be at a higher temperature than the ouside air
      • to keep from over-heating, proper ventilation is essential


  • The Greenhouse Effect
    • radiation from the Sun enters through Earth's atmosphere
    • some of it reflects back into the atmosphere
      • some escapes, but some gets caught in the greenhouse gases in the Earth's atmosphere
      • this radiation is then thrown in all directions, including back at the Earth
      • this is all natural, and helps regulate the Earth's temperature
    • humans are adding greenhouse gases into the atmospherethis causes more radiation to be caught in the atmosphere, effecting the climate of the Earth
      • burning fossil fuels
      • clearing forest
    • this is also what caused global warming

  • What are greenhouse gases?
    • 4 main substances
      • water vapor
      • carbon dioxide
      • methane
      • ozone
    • clouds also help absorb/reflect a small amount of radiation




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