This movie shows tech ed students' final parachute designs. Pay close attention to the flight path of the different chutes. Notice whether the canopy is stable or not, and very importantly, whether it is fully inflated throughout its fall.

Everyone can tell when there is catastrophic failure in a design: the car's brakes don't work when you put your foot to the pedal, a door handle spins freely instead of opening the door, or a parachute collapses and falls like a rock. Getting students to notice more subtle problems with their parachutes is a difficult yet worthwhile goal. One such problem involves the canopy alternating between being fully inflated and partly deflated. Getting them to reason about the cause-effect relationships between their parachutes' features and performance is an ultimate learning goal since students would then be doing informed designing rather than random trial-and-error guesswork.

Here are some parachute performance criteria that students can focus on in their investigations:

• Time of Descent -- This is the main measure of the model parachutes mentioned in the LBD's design brief. However, students can focus so much on their stopwatch that they miss cues about their parachute performance that they should try to alter by changing the design.
• Flight Path -- Does the model parachute fall straight down, at an angle, or oscillat while descending? Minimizing or avoiding oscillating improved the chute's overall performance.
• Inflated Canopy – Does the canopy remain fully inflated, or does it sometimes partial or fully collapse? Once inflated, the chute should stay inflated.
• Stability – Does the canopy remain balanced during descent, does it list to one side, flip over or oscillate while descending? Stable, even travel downward is better.