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Tuesday, November 23, 2010. Objective: Photosynthesis Lab! Bellringer : Draw a Photosynthesis “KWL” Chart over both Tuesday and Wednesday for this week. Today ( Tuesday ), you will fill in the K and W columns. Tomorrow ( Wednesday ), you will fill in the L column. BELL RINGER.
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Tuesday, November 23, 2010 • Objective:Photosynthesis Lab! • Bellringer: Draw a Photosynthesis “KWL” Chart over both Tuesday and Wednesday for this week. • Today (Tuesday), you will fill in the K and W columns. • Tomorrow (Wednesday), you will fill in the L column.
BELL RINGER Fill out the first two columns of the KWL chart. Leave the “L” column blank until tomorrow. 5 MINUTES
BELL RINGER Fill out the first two columns of the KWL chart. Leave the “L” column blank until tomorrow. 4 MINUTES
BELL RINGER Fill out the first two columns of the KWL chart. Leave the “L” column blank until tomorrow. 3 MINUTES
BELL RINGER Fill out the first two columns of the KWL chart. Leave the “L” column blank until tomorrow. 2 MINUTES
BELL RINGER Fill out the first two columns of the KWL chart. Leave the “L” column blank until tomorrow. 1 MINUTE
Using Elodea to demonstrate Photosynthesis6CO2 + 6H2O light>C6H12O6 + 6O2
How can we determine if photosynthesis occurs? • Bromothymol blue is a chemical that will be blue at pH around 7.6 and yellow-green at pH of 6 • CO2 can turn into carbonic acid when combined with water • If you blow through a straw into a solution of bromothymol blue, some CO2 will turn into Carbonic acid (so if enough CO2 is present in a bromothymol blue solution, it will have a yellow-green color.) • If an initial color of yellow-green turns blue, then what can you infer?
On your lab worksheet… • What question are we trying to answer by completing this lab? • As a pair, make a hypothesis. Based on what you know about photosynthesis and what you have just learned about bromothymol blue, do you think the presence of light will affect photosynthesis and cause a change in the color of the bromothymol blue solution?
Lab Set-up EL L D ED • Label your beaker with your Period and Group Number. • Label your 4 test tubes: EL, ED, L, and D • Carefully (SUPER SLOWLY) use your straw to blow air into the beaker. Continue until your solution turns a yellowish color. • Place each of your 2 Elodea pieces in the 2 test tubes labeled Elodea Lightand Elodea Dark (1 piece per test tube). • Pour 10 mL of the bromothymol blue solution into each of the 4 tubes (enough to cover plants). • Cap each test tube. • Cover the test tubes labeled Elodea Dark and Dark Controlwith the aluminum foil (make sure the entire tube is covered so no light can get through). • Place all test tubes in the empty beaker, (make sure your beaker is labeled) and set the beaker on the window sill. • Answer the remaining questions for Day 1 on the lab hand out. Elodea + Light Elodea + Dark Light Control Dark Control
Debrief/Wrap up • NOS • How does the lab demonstrate that science is tentative? • How does the lab demonstrate the concept of observation vs. inference? • Was there anything subjective about the lab? • Are there any other NOS categories that you can relate to this lab? • KOI • In this lab, did we test a hypothesis? • Was our procedure guided by a question? • Give an example of how our procedure could have influenced our results. • Did we all get the exact same results? Why or why not? • Were our conclusions consistent with our data? • Explain how in this lab data and evidence are not the same.