Caitlin's+Project+ch+10

**By: Caitlin**
 * Plants and Radiation**

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 * **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

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 * **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



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 * **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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