Chapter 11
Designing Experiments
Bob: Hi, Jay. Thanks for making it over.
Jay: Glad to be here. Who else is here
already? The game should be
starting soon.
Bob: Mike and Dave are in the den,
watching the pregame show
and finalizing their fantasy
teams. I think we’ve got about
15 minutes before kickoff.
Jay: Sounds good. Hey, what’s that
smell? Is something burning?
Bob [runs to the kitchen]: Whoops! I
thought the guys were watch-
ing the stuff they brought. [Frantically pulls on some oven mitts
and slides out a tray of burned mozzarella sticks and chicken
wings.] Open the window!
Jay [pops open a window and fiddles with the remote control for the ceiling
fan]: That’s a lot of smoke.
Bob Leibe describes his son’s science
fair project—popping the perfect
cornto his friend, Jay, who has come
over to watch a football game. He
describes their process for identifying
variables, as well as their objectives and
definition of success. Last, he discusses
the results of their research, which
include insight into which variables
have the greatest effect on the outcome.
As you read Bob’s story, think
about what he and his son might do
next to continue the popcorn improve-
ment process.
Bob: Give me that. [Reaches for the remote control and puts the fan on high
speed.] Well, what are we going to eat now? Beer alone isn’t
enough. I’ve got to eat something, or my ulcer will act up.
Jay: I don’t think anyone’s going to want to go to the store again. What
do you have in the house? Can we make some popcorn or
Bob: Good idea. [Closes the window now that the smoke has cleared.] I
make the best popcorn this side of the Mississippi.
Jay: How could you possibly know that your popcorn is the best?
Bob: Because Malachi and I have popped a batch every day for the
past month as part of his science project. For some reason, I
haven’t gotten tired of eating our research.
Jay: What’s the science project about? I’ve got to do something similar
with Vicky next month, and I could use some ideas.
Bob [gets his popcorn equipment out and opens a cabinet to reveal 12 bags of
popcorn from different manufacturers]: We designed the project
to demonstrate how to control several variables in a process
to standardize and optimize the outcome.
Jay: What does Sandy have to say about all this?
Bob: She loves it. We always clean up the kitchen after conducting our
top- secret activities. I usually cooked dinner anyway before
we started this project because she worked late, and then she
did the dishes—now it’s easier for her because she gets din-
ner and a clean kitchen.
Jay: You’re a real treasure!
Bob: Yeah, tell me about it. Anyway, we started the project by taking a
look at the variables that we guessed would have the great-
est effect on the outcome. We first looked at six variables,
and we went back and forth about which ones were the most
important. We wanted to design the project in the way we
thought it would be most effective. When we first started
talking about it, we looked at the brand of kernel, the thick-
ness and density of the pan bottom, lid seal tightness, pop-
ping medium (oil or air), gas or electric stove, and toppings.
Jay: How would you even know where to start? That’s not a very spe-
cific list. You could test those things forever and not come up
with anything definitive. Don’t science experiments isolate
one or two things, so the outcome is more controlled?
Bob: Yes, that’s true, but Malachi enjoys debating the minutiae, so we
delved quite deeply into the details of those six things on our
initial list. First of all, we have an electric stove, not a gas
range. So we thought about that. We realized that our gas-
versus- electric line item was more a matter of the ability to
control temperature. For the purposes of this experiment, we
realized that we could simply preheat an electric stove burner
so that the popcorn pan was introduced to high heat fairly
quickly, the same way as a gas stove. We also lowered the
heat inside the popcorn pan by moving it to another burner
that was not currently in use to duplicate the superior tem-
perature control of a gas stove. Therefore, for the purposes
of this experiment, we removed that variable from the list.

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