Oct 06 2009
Controlled Experiments
I just have a quick question kind of like the one I asked in class today. I’ll use our feat practice response as an example, the one about moths population and how it’s affected acorn production.
Would I have been able to just OBSERVE the moth production once during the acorn autumnal season where there are a lot of acorns and then observe it again during the acorn season?
Im not specifically changing something my self, and I’m not sure if the two obaerations could be considered a controlled experiment.
Thanks!
Okay Richard, I do think that an observational experiment would have been okay to use for our sample essay. If you’re like me, I thought that “observational experiments” were done by just sitting back and watching what is going on. Instead, I now understand it to be when you take measurements without manipulating a variable. In our essay, we could have counted (“observed”) the moth population over a number of oak tree cycles. We wouldn’t be manipulating anything, but we wouldn’t be passively sitting back and watching–we would record measurements.
Check out the scoring guide that Mr. Willard used to grade the essay. It mentions observational experiments.
Good, Caroline. And yes, you could use a year of low or no acorn production as a baseline, then compare those counts to years when there was a lot of acorn production (vs. some other variable like moth numbers). You just don’t manipulate a variable. The control is the baseline measurements. You still try to keep constant area, time, etc…