Lab #5 PhotosynthesisS61

Procedures:

www.kabt.org/2008/09/29/video-on-sinking-disks-for-the-floating-leaf-disk-lab/

AP LAB: Photosynthesis•Procedures:– 1. Prepare 300mL of 0.2% bicarbonate solution for each experiment.(CO2)– 2. Pour the bicarbonate solution into a clear plastic cup (100 mL). Label

cup “w/CO2”– 3. Fill the second cup (100 mL) with water. Label this “w/o CO2”– 4. Add 1 drop of diluted liquid soap to each cup.– 5. Using a hole puncher, cut 10 or more uniform leaf disks for each cup.– 6. Obtain 2-10cc syringe and place 10 leaf disks inside the each barrel.

Replace the piston, be careful not to crush the leaf disks. Push in the plunger until only a small volume of air and leaf disk remain.

– 7. Pull a small volume (5cc) of sodium bicarbonate + soap from your cup into one syringe and a small volume (5cc) of water + soap from your cup into the other syringe. 8. Make a vacuum in the plunger to draw the air out of the leaf tissue. (This is the most difficult step to master).

– 9. Pour the disks and solution from the syringe into the appropriate cups.– 10. Place both cups under the light source and start the timer. After every

minute, count the number of disks floating. Continue until all the disks are floating.

– 11. Record your data– 12. NOW: test 2 other variables and collect data.

Lab #5 Photosynthesis

•Questions????•1. What variables of the plant leaves might affect the net rate of photosynthesis?•2. What environmental factors might affect the rate of photosynthesis?