Design Variables and Their Effects
A design variable is something in the product you can
change that can affect the product's performance. These
design features are like independent variables in an equation.
The outcome (or dependent) variable is the product's performance
that you observe qualitatively or measure and record quantitatively.
The main goal of this portion of Key Concepts is to review
the variables in a model parachute's design, describe their
effect on parachute performance, and discuss the science
that lies behind these behaviors. The following are some
of the ways students can vary the design of their model
parachutes. You may want your students to brainstorm for
these ideas during their initial discussions of variables:
Number of canopy layers
Number of Strings
Vent holes (holes or slits)
Frame for canopy (or not)
HINT: Before giving having students talk about the effect of these variables on
parachute performance, review the discussion of What To Observe (besides time)
as this may effect how you have them test and improve their parachutes.