Mechanisms of Herbicides

Grades 9-12.

Designed to demonstrate the effectiveness of different categories of chemical herbicides. Users will transplant grasses and weeds into flats or pots and investigate how and why different plants are killed by different chemical herbicides. A simultaneous microbiological proof with inoculated agar plates is run to reinforce the results, further categorize herbicides, and determine possible effects of the herbicides on soil microorganisms. Each group will choose two natural products and design a simple experiment to compare chemical vs. natural weed killers. A round table discussion including experimental designs, results, comparisons, and possible environmental impact culminates the exercise. Required (not included): heat source, flower pots or nursery flats, and grass and weeds for transplanting. Designed for 24 people working in groups of four.