DAY 2: Bring on the Caterpillars: Journals and Intro to Scientific Data Collection (20 min)
1. Before the students receive their caterpillar (oh, what a moment!) they need to learn about the importance of good scientific journal keeping. My handout includes a list of 5 main points on which the students should focus in their daily entries:
- (1) Description of appearance
- (2) Behavior
- (3) Sketches
- (4) Measurements
- (5) Comparisons to other butterflies in the class
Emphasize the importance detailed observations and of making observations only (no inferences!) in order to avoid bias. I also explained that the words larvae and caterpillar are synonymous, and made sure my students were spelling them correctly.
2. Assign a larvae cup to student pairs. The larvae will arrive in two's inside a small, clear plastic cup, complete with food to last. Label the cups by letter. Students must immediately choose one of the caterpillars as "theirs," which will likely require very careful observations of appearance and behavior. Emphasize this point to the students.
3. Initial measurements should be made with a metric ruler, to the bests of the students abilities -- they may have to estimate, if the caterpillars are not stretched in a straight line. Students should take the time to carefully sketch their caterpillar, and to compare it to others in the class.
Example Student Sketch of Painted Lady Larva
Alternatives: Measure the mass of the caterpillars. The method suggested for transfer of the larvae is by paintbrush, so as to avoid damaging their fragile bodies. I chose to not have the class do this for fear of disrupting the larvae too much, but I think that this would be a more accurate measure of growth if coupled with the length and width estimations. I would try this the next time I set up this project.
