Docstoc

PHOTOSYNTHESIS LAB GIZMO (DOC)

Document Sample
PHOTOSYNTHESIS LAB GIZMO (DOC) Powered By Docstoc
					                     PHOTOSYNTHESIS GIZMO LAB

Directions: Go to the web-site: www.explorelearning.com. Sign in using
Mrs. Craun’s username and password. Follow the directions listed below
step by step. Any questions that are italicized require an answer. Make
sure you write in complete sentences.

Pre-lab:
  1. Write the chemical equation of photosynthesis.



  2. What are the reactants of photosynthesis?



  3. What are the products of photosynthesis?




Part 1: Effect of Light Intensity on Photosynthesis
  Step 1: In the gizmo, observe the aquatic plant. During photosynthesis,
  the plant produces oxygen, which is visible as bubbles leaving the plant.
  Set the Light Intensity to 0%. Check that the Temperature slider is set
  to 30.0C and the CO2 level is set to 5.0%. Then select the bar chart.

           a. What is the rate of oxygen production?




           b. What does this tell you about the rate of photosynthesis when no light is
              present? Explain your answer.




     Step 2: Slowly drag the Light intensity slider to the right.

           a. What happens to the rate of oxygen production as the light intensity
              increases?
  b. What does this tell you about the rate of photosynthesis as the light
     intensity increases?



  c. Does increasing light intensity always have the same effect on oxygen
     production? In other words, are there certain light intensity changes that
     have no effect at all? Describe what you see.




Step 3: Select the TABLE tab. You will now use the table to record
data on oxygen production at different intensities of light. Set the
Light Intensity to 0%. Click on the record data button to record this
information in the table.Record the oxygen production when the light
intensity is 10%, 20%, 30%, and so on up to 100%. Be sure to click
on RECORD DATA each time so all of the data is recorded in your
table.

      a. Does your data agree with your findings that light intensity effects O2
     production? Explain.




Step 4: To view a graph of your data, select the GRAPH tab. Be
sure that INTENSITY is selected from the options below the graph.

     a. Draw the graph below. Make sure to put line.




     b. Does your line graph support your statement from Step 3 above?
Part II: Effect of CO2 level on Photosynthesis
      Step 1: During photosynthesis, plants use CO2 as a source of
      carbon, which is used to build an energy-rich sugar called glucose.
      The purpose of this part is to determine if the amount of CO2
      available influences the rate of photosynthesis. Click on BAR CHART
      tab. The CO2 level indicates the amount of dissolved CO2. Set the
      LIGHT INTENSITY slider to 90% and the TEMPERATURE to 30.0C.
      Set the CO2 level slider to 0.0%.

           a. What is the rate of oxygen production when there is no carbon dioxide
           available?




     Step 2: Slowly drag the CO2 level slider to the right.

              a. What happens to the rate of oxygen production as the CO2 level
                 increases?




              b. What happens when the CO2 level exceeds 3%?




Part III: Effect of Temperature on Photosynthesis
      Step 1: The production of sugars in photosynthesis is the result of a
      sequence of chemical reactions. Each reaction is sensitive to the
      temperature at which it take place. Depending on their environments,
      different plants will undergo photosynthesis most efficiently at
      different temperature. Set the LIGHT INTENSITY to 90% and the
      CO2 level to 10.%. Set the TEMPERATURE to 0.0C and select the
      BAR CHART tab.

                 a. What is the oxygen production when the water temperature is
                    0.0C?


                 b. What does this tell you about the rate of photosynthesis when
                    the temperature is 0.0C?
     Step 2: Slowly drag the temperature slider up.

                  a. What happens to the rate of oxygen production as temperature
                     is increased?



                  b. What happens to the rate of oxygen production when the
                     temperature exceeds 25C?




Part IV: Effect of Color of Light on Photosynthesis
      Step 1: White light is a combination of different colors of light. The
      specific color of light we see is determined by its wavelength, which
      is measured in nanometers (nm). Select the COLOR tab and the
      BAR CHART tab. Set the Light INTENSITY to 90%, CO2 to 5%,
      Temperature to 30.0C, and LIGHT WAVELENGTH to 400nm.
      Slowly drag the LIGHT WAVELENGTH slider to the right.

           a. Describe what happens to the rate of oxygen production as you drag
              the LIGHT WAVELENGTH slider to the right.




Conclusion: Summary of Results

     a. Explain how the rate of photosynthesis is affected by each of the following:
                    increase in light intensity:



                       increase in CO2 level:


                       increase in temperature:


                       increase in wavelengths of light: