Roach and Ant Spray deaths over time (Erica Brauer)
Research Question and Hypothesis
How many Daphnea Magna will die at different concentrations over the span of 3 hours?
Extension:
How many Daphnea Magna will die at different concentrations over the span of 3 hours in an organic ant and roach killer? Or a home remedy?
Standards
SEP 3: Planning and Engineering Practices
SEP 4: Analyzing and Interpreting Data
CCC 3: Scale, Proportion, and Quantity
CCC 7: Stability and Change
5-ESS3-1. Obtain and combine information about ways individual communities use science ideas to protect the Earth’s resources and environment.
Experimental Design
Students will see how different concentrations of a chemical can effect the percent mortality over time. Students will prepare 3 containers with ant and roach killer at different concentrations. They will then add Daphnia Magna to the solution, and monitor the number of organisms that are still alive at each time interval at the different concentrations.
Independent variable
The independent variable is the time. We will make serial dilutions of the chemical to establish specific, incremental concentrations.
Dependent variables
The dependent variable is the number of Daphnia magna surviving. We will count the surviving individuals after a certain amount of time.
Series
Study the number of deaths (dependent variable) as a function of time (independent variable) at various concentrations of Ant and Roach killer (series).
Constants and Controls
The concentrations will be held constant in each experiment. We will use 3 different concentrations: 100 ppm, 10 ppm, and 1 ppm. The control will be a cup with just water, no Ant and Roach killer at all.
Materials
3 plastic soufflé containers per lab group
pond water
10 ml graduated cylinder
eyedropper pipet
Ant and Roach killer stock solution
Large supply of Daphnia Magna
Procedures
First, obtain 4 plastic soufflé containers and a water soluble marker.
1. Label the 3 containers as follows: Control, 100ppm, 10ppm, 1 ppm.
2. Add 45ml of pond water to the Control and 45ml of pond water to the other two containers.
3. Using a 10ml graduated cylinder and an eyedropper pipet (both of which have been rinsed in distilled water), carefully transfer 5ml of the ant and roach killer stock solution (1,000 ppm) stock solution to the soufflé container labeled 100ppm. Stir gently.
4. Carefully rinse the glassware and then transfer 5ml of the 100ppm container to the container marked 10ppm. Stir gently.
5. Repeat this for the 1 ppm container. (Remove 5 mls of the 10 ppm container so they all have 45 mls of solution.)
5. Using an eyedropper pipet, transfer 10 viable Daphnia magna into each of the plastic containers. Try to pick Daphnia of a consistent size.
7. Expose the Daphnia to the experimental conditions for three hours.
8. After each hour of exposure, carefully count the Daphnia to determine the percent mortality.
Input your data here
Sample data and graphs
View the summary of responses here
Analysis & Conclusions
Sample data as of now, but students should see be able to connect a few ideas:
1. As time increases, number of surviving individuals decreases.
2. As concentration increases, number of surviving individuals decreases.
3. If the control population decreases, this must be factored in to data overall.
Photos & Movies
Photos and Movies will be added in the future when this is done in class.
References
I have asked PHET to do a simulation for something similar to this, but as of right now, I am still looking for resources
*LAb adapted from Dan Hykes, AP Environmental Science Teacher and APSI Teacher