Environmental+Prefs+activity

Guiding question: Do pillbugs prefer hot or cold areas? Do sow bugs prefer hot or cold areas?

Provide brief content background about differences between pillbugs and sow bugs.

Have participants generate a hypothesis.

Discuss: A controlled experiment begins with a hypothesis, a proposed solution for the problem being investigated. A hypothesis is often written as an IF, THEN statement that predicts the outcome we should expect if the hypothesis is correct. A hypothesis should not only predict results; it must be testable.

Examples Poor: I think both pillbugs and sow bugs will move toward the wet side of a choice chamber. Better: If pillbugs and sow bugs prefer a moist environment, then when they are randomly placed on both sides of a wet/dry choice chamber and allowed to move about freely for 10 minutes, most will be found on the wet side.

Experimental set up: Show materials to participants. Have participants discuss in groups of 4 how they should set up and design the experiment. Share designs.

Discuss: In a controlled experiment, you must explicitly keep all variables constant except the one you are manipulating. For instance, if you want to test response to hot vs. cold conditions, the light, temperature, moisture, chemicals in the filter paper or on the dish surface, and movement of the table must all remain constant. In addition, all the experimental organisms must be of the same approximate age, size, and state of health.

To be meaningful, your experiment must include a large enough sample size to be representative of a general condition. How many pillbugs should we use?

Your results must be measurable. Are you going to count, measure, find the mass? How are you going to quantify the results?

How long should the trial run? (10 minutes).

How many times should we replicate the experiment? If each group conducts the same trial, then we have multiple trails and can calculate averages.

Procedure: For this experiment we will use 10 pillbugs. Ask how many pillbugs should we initially place in each chamber (5 each).

Place a hand warmer on one end of a Pillbug choice chamber (Carolina Biological) and an ice pack on the other end of the choice paper.

Observe pillbugs for 10 minutes. Record observations during trial. What behaviors do pillbugs exhibit?

At the end of the trial, measure the temperature of the chambers with pillbugs in them with Pasco temperature sensor.

Data collection and analysis:

Pool data in chart:

Pillbugs Hot Cold Group 1 Group 2 Group 3 Group 4 Group 5 Group 6 Group 7 Average

Sow bugs Hot Cold Group 1 Group 2 Group 3 Group 4 Group 5 Group 6 Group 7 Average

Formulate Conclusion:

Have participants analyze data and formulate conclusion.

Alternative Explanations:

Have participants generate a list of other abiotic factors that might influence pillbug preferences in an environment.

Moisture Color Soil composition

Experimental Design Task:

Assign each group an abiotic factor (moisture or color) and have groups generate a hypothesis.

Write out the procedure for an experiment to test the new hypothesis. Carry out the experiment. Afterwards, share data and conclusions with all participants. (Provide overhead transparencies and markers to each group).

Discuss classroom communication ideas for students. Mini-poster, Powerpoint presentation, oral reports, data displays.

Materials needed: For each group: 10 pillbugs or 10 sow bugs Pillbug preference chamber Hand warmer Ice pack

Sorting brushes Foil Colored paper