LC50: How Much is Too Much? Lab Activity

Bioassays that Glow

• Aligned to Fundamental Frameworks Concepts PS1 and ESS3
• Pre and post laboratory assessments
• Linked to a real world scenario
• Estimated class/lab time required: 45 minutes

Students will conduct a bioassay demonstrating the toxic effects of copper sulfate (a common algaecide) on a population of Daphnia. They will feed the Daphnia a fluorescently-tagged sugar after exposing them to various concentrations of copper sulfate. Only the healthy Daphnia will glow under long-wave UV light. Students will then pool their data to predict the lethal concentration necessary to cause 50% mortality and arrive at an overall LC50 value for the entire class. Students will employ fundamental frameework concepts of Matter and Its Interaction (PS1) and Earth and Human Activity (ESS3) while completing this lab activity.

This kit has been aligned with all published National Standards. Pre- and Post-laboratory assessments and vocabulary words all target specific Science and Engineering Practices and common core standards. The teacher guide also contains specific "Did You Know" concepts that link the real world with the scientific standards explored. Materials are included for 15 setups.

Materials included:
Daphnia magna cultures
CuSO4 solution (0.5 ppm)
Tagged sugar vial
Medicine cups
Disposable pipets
Food coloring
Plastic vials and caps
Plastic cups

Materials not included
UV Light or “black light”
UV Protective goggles
Beaker or small container
Distilled water
Scissors

Time requirements:
This lab activity takes approximately 45 minutes to complete.