Earth And Space Science Project Abstract
CHANGES IN ELECTRICAL RESISTANCE OF PLANT LEAVES
Presenter:
Emily J. Rice, Illinois Mathematics and Science Academy, 1500 West Sullivan Road, Aurora, IL, 60506; ricerice@imsa.edu
Advisor:
Dr. David Workman, Illinois Mathematics and Science Academy, 1500 West Sullivan Road, Physics, Aurora, IL, 60506; 630-907-5915; workman@imsa.edu
Abstract:
Cleve Backster claims that plants exhibit physiological changes in response to the death of brine shrimp in their environment. Attempts to reproduce this work have failed, but scientists did note that the electrical resistance of the plant leaves changed, although it did not correspond to the specific time that the shrimp were killed. This Inquiry project attempts to measure the electrical resistance over time of philodendron, geranium, and other types of leaves to determine the cause of these changes. Measuring resistance by puncturing the leaf with the electrodes, using alligator clips, putting the electrodes directly against the sides of the leaf and applying pressure, and using gauze pads soaked in saltwater containing agar between the leaf and electrodes have been tried and failed. The next step is to sandwich the leaves and saltwater, agar, and gauze mix between two squares of aluminum foil with electrodes attached to the foil, avoiding several problems inherent in the other methods. Once a method of measuring the electrical resistance of leaves is determined, changes of electrical resistance in plant leaves under different levels of light, temperature, and water, among other variables, will be measured.