| Variables & Fair Tests |
The notion of "fair-test" experiments comes from the United Kingdom, where this phrase is used as more accessible alternative for students than them doing the "scientific method." Developmentally, quite young children (age 6-7) have a workable notion of fairness, which they can apply to test settings, and involves maintaining experimental conditions across tests and controlling variables in a reasonable way so that usable testing data gets generated.
Designers conduct experiments in their work -- they observe users engaged with prototypes. They collect data, too, though not to the extent that a scientist would. Someone designing the lid and seal of a jar needs to determine that typical users can open the lid without a struggle. Still, the seal must be maintained well enough so that unintended openings are avoided. The scientist typically would want to conduct large number of tests in evaluating hypotheses they have proposed. They might want to determine the forces at work that determine a good seal -- aiming to understand the science of lids. On the other hand, the designer would be dealing with time (and money) constraints, which would limit them to doing just enough tests for them to come up with an informed design decision.
These movies show one tech ed and two science teachers leading discussions about what the key variable are that can affect a model parachute's performance. In all three sequences, discussions occurred after students had "messed about" with the materials and experienced how a basic model parachute works and falls. Watch for differences in these teacher led discussions - Can you glean the different general learning and content goals of the three teachers? What strengths does each bring to this topic's conversation? What is your view of how "Whiteboarding" organizes and prioritizes students thinking about this topic?
Afterwards, students went back to their work tables to explore and test individual parachute features and report on their findings. For years, students hear about the "scientific method", but in the ensuing days' work, notice how the excitement of creating a new design idea takes over. Admonitions to set up good testing conditions, control one variable at a time, do multiple tests, and measure outcomes carefully often go by the wayside in the heat of designing.