1. Photosynthesis Stations

2. Light or Dark? Bromothymol Blue is an indicator that is blue in the presence of O2, and turns yellow/light green in the presence of CO 2. Observe all the test tubes. Observe the tubes placed in the dark for 48 hrs. 1)Why do you think all of the tubes, except one, are still yellow, even in the presence of plants? Observe the tubes exposed to sunlight for 48 hours. 2)Why do you think one out of the 4 tubes is still yellow? 3)What is the snail releasing that is keeping the tube yellow? 4)What is the plant releasing that is keeping the tube blue?

3. CO2 Reactant or Product of Photosynthesis? Fill empty flask with 150 ml’s of water. Please be sure everyone in the groups is wearing an apron! Put about 20 drops of bromothymol blue indicator into flask One person in the group, put on goggles, take a clean straw, mix the blue thoroughly in water. Compare the flask you just mixed to the control. They should be the same color. Now blow through the straw and observe what happens. 1)What happened to color when blowing into the straw? 2)What molecule are you blowing out that caused the color change?

4. Stomata Observe the underside of leaf under the microscope Notice the stomata (openings). These openings (stomata) are the little “mouths” that the plant uses to “breathe”. 1)What gas does the plant breathe in? 2)What gas does the plant breathe out? The stomata are closed at night. 3) Why do you think they are open during the day?

5. Veins Observe the top of leaf under the microscope. Notice the veins (bright lines running through it) Observe the leaf samples, do they have veins? 1)What does the plant need that travels through these veins? 2) What is the name of the bundle of tubes within the veins that carry H 2 O to the cells (pg.181 last paragraph) 3)How are these veins similar to ours?

6. Leaf Cross-Section Observe the cross-sections of the leaf. 1) What energy source is hitting the top of the leaf? Notice the location of the chloroplasts 2) What important process takes place in the chloroplasts? 3) In what layer of the leaf do you think most of the photosynthesis occurs?

7. The Carbon and Oxygen Cycle Analyze the Carbon and Oxygen Cycle 1)What is the energy driving the cycle? 2)What are 3 ways in which CO 2 is released into the air? 3)What are 2 ways in which Carbon is absorbed into the ground? 4)What process is recycling the CO 2 into O 2 ?