How Do Different Light Wavelengths Affect Planaria?

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Alec Long
3/29/13
2nd Hour
How do Different Light Wavelengths Affect Planaria?
1. Background Information
* Non-parasitic flatworm
* Some have 2 eye spots, while others have several more
* Move away from light
* Have three germ layers- estoderm, mesoderm, and endoderm

2. Problem
How do different light wavelengths affect Planaria?

3. Independent Variable
Color of light

4. Dependent Variable
Reaction to light

5. Experimental Group
Group that receives the lights

6. Control Group
Group that receives normal lighting
7. Controlled Variables
* Brightness
* Temperature of water
* Distance from light bulb
* Size of container
* Amount of time exposed to light

8. Hypothesis
If the Planaria are placed under the colored lights, then they will move away from and curl up farthest from the light and try to avoid it as much as possible because it’s in their nature to avoid the light and their eyes are very sensitive to them.

9. Materials
* 1 medium-sized containers
* 100mL beaker
* 2 lamps
* 3 bulbs (normal, red, and black)
* Ruler
* 2 timers
* Cardboard pieces
* Scissors
* Tape
* Thermometer
* Microscope
* 6 Planaria (Dugesia tigrina)
* Fresh water

10. Procedures
Pre-lab:
1. Make sure all supplies are present
2. Pour 50mL of fresh water into beaker
3. Check the water to make sure it’s at room temperature 4. Pour water into medium sized container
5. Set up lamp with correct bulb for trial
6. Use ruler to measure 12 inches between the bulb and water 7. Place cardboard in such a way that only the lamp light shines on the planaria Lab:
1. Place planaria in water
2. Start with using the normal light
3. Use one timer to time the light over the water for one minute and thirty seconds 4. Use the second timer to time how long the planaria takes to react 5. Record any reaction or data
6....
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