How do bombardier beetles defend themselves?
Katrina Lustofin
(lustofin@uiuc.edu)
(ready to use)
ASK
Partner Projects
| GK-12 Teaching Fellowships |
Subject Areas
Grade Levels
Unit Keywords
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bombardier beetles, chemistry, exothermic reactions, entomology |
Rationale of the Unit
| This unit examines exothermic reactions in chemistry using bombardier beetle defense as a model |
Background and Resources
Activities and Open-ended problems
See attached word file for lab exercise
See attached excel file for calculations
The endproduct is mildly irritating to the skin, plus hydrogen peroxide at 30% can be irritating, so we had the students wear gloves. |
Dialogues, Discussions, and Presentations
Discuss how to do the calculations involved. Discuss exothermic and endothermic equations.
We also ended up discussing units of measurement. The students were curious as to why I would write 0.24 micromoles instead of 2.5 x10^-7 moles. Also, they had not worked with anything other than grams, milligrams and kilograms (or liters, ml, kl, etc) so micro-units were new, as was the idea of millimoles or micromoles. We discussed why the units were so small, in relation to insect size. |
Assessment, Related Questions, and Story of the Unit
| Our reactions generated heat of about 45 degrees Celsius and quite a bit of foaming. The students found this somewhat exciting. The calculations were very difficult for the students, particularly since they were not used to converting between grams and micrograms. For future use, I might assign the calculations ahead of time to give the students more lab time. |
Uploaded Files:
bombardiermath.xls
BombardierbeetleLab.doc
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