Leaf Disk Lab Report

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Introduction: Leaf Disk float in water alone. When a solution consisting of a small amount of sodium bicarbonate is added to the water it causes the leaf disk to sink. As photosynthesis continues in the leaf disk it releases oxygen and causes the leaf disk to rise. While cellular respiration is occurring also the rate that the disk raise is an in implicit measurement of the net rate of photosynthesis. The independent variable in this lab is the solution and the light because it can be controlled. The dependent variables are the leaf disk because they cannot be controlled. After at least 10 minutes I think that some of the leaf disk will float in the bicarbonate/soap solution in the light.
Methods:
1.Label 3 beakers a. Bicarbonate/soap—light
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Fill each of the cups around 1/3 full of each of the following solutions. a. Bicarbonate/soap—light b. bicarbonate/soap—dark c. water/soap
4. Hole punch 10 uniform leaf disks for each o the 3 trials using the hole punch. Avoid the major veins of the leaf.
5. Infiltrate leaf disks with the appropriate solution. Be sure syringes are VEY clean so you do not cross contaminate them with bicarbonate. a. Remove the plunger of the syringe and place your leaf disk in the syringe barrel. b. Replace the plunger, being careful not to crush the leaf disks. Push on the plunger, being careful not to crush the leaf disks. Push on the plunger until only a small volume of air and leaf disk remains in the barrel. c. Put a small volume of the appropriate solution into the syringe. Tap the syringe to suspend the leaf disks in the solution. d. Hold a finger over the syringe opening; draw back on the plunger to create a vacuum, swirl the leaf disks to suspend them in solution then let off the vacuum. All of the disks should sink.
6. Pour the disks and the solution into the correct cup.
7. Place both cups under the light source and start the timer.
8.Record how many disks are floating at the end of each minute and record in the data

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