Prelab 9

Josh 12/10/06 AP Bio 2 Lab 9 Pre-lab Assignment 1. Hypothesis: If a gentle breeze is present near a plant, then the rate of transpiration of the plant will increase. 2. The control group is a plant under room conditions. 3. The dependent variable is water loss in milliliters per meter squared. 4. The independent variable is time. 5. The variables temperature, pressure, and apparatus setup will be held constant. 6. Water loss from the leaves in milliliters per meter squared is being measured. 7. Method and Time Frame: A potometer will be used and readings of the water level in the potometer will be taken every 3 minutes for 30 minutes. 8. The rate of calculation is the slope of the curve. 9. The class data will be accumulated. to verify the results. 10. The results will be presented by a graph and a chart. 11. The expected results are that the rate of transpiration will be greater when a light breeze is present near the plant because the rate of evaporation will increase and more water will be forced up the xylem. The breeze will not be great enough to induce the stomata to close more often and slow down transpiration.