Teachers have little time for individual diagnosis and instruction
-- they have to get good at recognizing patterns of
behavior and shape their teaching responses to a handful
of patterns rather than a gradebook full of students.
This page's movie shows an 8th-grade class in Atlanta
doing their first parachute drops -- they were finishing
the second day of work. Look for trends in the way the
teams' chutes behave.
Most of these parachutes are collapsing in mid-flight
-- they are failing to meet one of three parachute Key
Criteria -- a canopy should inflate quickly and
remain fully inflated through its entire descent. While
it is not intuitive, one approach to achieving full
inflation is to increase the load (few students elect
to do this). The larger the canopy, the more airflow
is required to keep it from becoming partially under-inflated.
Such chutes are more stable when there is a cross-wind.
What would you do if you had a class that basically
was proposing the same design, with only minor variations?
The next day, the teacher had each team investigate
a different issue: (1) Ancient History - report on first
parachute designs; (2) Recent History - team members
interviewed other teams about designs; (3) Indoor/Outdoor
Drops - reported on how chutes dropped outside might
behave differently than indoors; (4) Make Invisible
Visible 1- draw flight path of different chute drops;
and (5) Make Invisible Visible 2 - draw what the airflow
might be as a parachute descends.
After the lesson, teams in this class produced much
more varied designs -- this was the teacher's main goal
of the activity. Students' explanations for their design
decisions were also noted as more detailed afterwards.