Toxicology Enrichment Materials
Find the Toxic Dose
Teacher's Notes
Introduction: This laboratory exercise will help introduce your biology, chemistry or physiology class to the science behind many contemporary issues. Testing new drugs and determining cause and effect relationships between the presence of chemicals in the environment and detrimental effects on wildlife are examples which draw on the basic principles of toxicology. This lab will help students understand the concept of dose vs. response.
Features: As we know from the famous quote from Paracelsus, all chemicals are poisonous. The students will be allowed to choose their own chemical to deduce its toxicity to a germinating seed. The materials are readily available, the experiment takes a small amount of space, and it takes a limited amount of time over the course of a week. Mathematical principles are emphasized when they use serial dilutions to establish a dose range. The experiment can be adapted to emphasize botany, algebra, graphing or the relationship between different chemicals (for example, comparing different acids or bases).
Scientific Writing: The exercise is not written with "cookbook" instructions. Instead, only guidelines are provided. To emphasize scientific writing, have students write their results in the style of a scientific paper.
Introduction: - purpose of this type of experiment - choice of chemical and dose range - type of information hoped to gain
Materials and methods: - source of chemical - treatments, dilutions - seeds, containers, wicks, etc.
Results - organized presentation of all observations - tables, graphs, drawings
Discussion - conclusions - significance of results (relate back to introduction) - proposal of further experiments
Materials: Brassica rapa seeds are available from Carolina Biological Supply (as are other Wisconsin Fast Plants materials) or adapt the experiment to use seeds from other plants. Seeds that are relatively large will probably fall off the wicks as they are used in this experiment. You will need to set up a horizontal, rather than vertical, wick arrangement.
This laboratory exercise was adapted from materials written by Wisconsin Fast Plants Program, College of Agriculture and Life Science, University of Wisconsin-Madison. www.fastplants.org
[Author's Note] [Toxicology Terms] [Toxicology Careers] [Toxicology and Biological Organization] [Some Basic Principles of Toxicology] [Find the Toxic Dose] [Topics in Toxicology] [Toxicology on the World Wide Web] [Table of Contents]
