# The SimRocket Sessions from the Teacher’s Perspective

In Spring 1998 a group of five boys at a local middle
school chose to do a science project on model rockets. The seventh graders were
approximately 13 years old. For purposes of this document, they will be referred
to as Jamie, Chuck, Steven, Kelly and Brent (see **picture
1**). Their teacher asked me if I would like to volunteer to mentor their
project. Science projects were generally mentored by adults from the community.
I was introduced to the students as a scientist at the local university who had
developed a computer simulation of rocket launches. The students actually
already knew me because I had been involved with introducing an unrelated
software program to their class earlier in the school year. I met with the
students for two sessions, each about 1 ˝ hours long. Fortunately, I had both
sessions videotaped.

In session A, I introduced the students to **the
simulation software** in a small room adjacent to their classroom. We
discussed rockets a bit and spent most of the time firing off several simulated
rockets and writing down how high they went. In session B, we fired some more
rockets, consolidated all the data collected, computed the effect of different
rocket characteristics and successfully predicted how high an eighth rocket that
had not yet been fired would go. Between my two meetings with them, the students
built and tested model rockets made from large soda bottles and filled with
water under pressure.

My agenda as a researcher was to see if the students
understood or could discover one of the basic principles of experimental
science, namely the principle of isolating a single independent variable (such
as the shape of the rocket’s nosecone, which could be either pointed or
rounded). That is, to see the effect of the nosecone shape on the height of a
rocket flight, one should take two rockets that are identical in every
characteristic except nosecone shape and compare their flights. Accordingly, I
set up the simulation with 8 rockets that differed in terms of their nosecone,
fins, texture and engine. The **list
of rockets** was devised so that one could find pairs of rockets that
isolated each of the variables. And an 8^{th} rocket differed from the 1^{st}
by each of these variables, so that it’s flight height could be predicted by
adding the differences computed for each of the variables. The simulation in
fact used a computation that did just that: it added up the independent effects
of the variables. However, it also included a random “noise” factor so that
a given rocket had to be fired several times to find out its average height.

As a mentor to the group, I never explicitly stated the
principle of isolating variables. In fact we never talked about “variables”
or “isolating.” I simply responded to the situation we were in at any given
moment and tried to guide the group to solve the problem posed by the simulation
by suggesting to the students how I would think about the problem and work on
it. Mostly, I made these suggestions by posing questions for the students to
think about and discuss.

The computer simulation was available at **http://GerryStahl.net/previous/simrocket**
and was accompanied by a web page of instructions. The instructions posed the
question: how high will rocket 8 go? It listed the characteristics of each
rocket, highlighting the differences between successive rockets visually.

The students worked at two computers, firing each rocket
several times. For each firing, they noted its highest point and recorded that
on a chart I had printed out for them. After rockets 1 through 7 were fired 6
times by each group of students, we compiled all the data on **one
chart**.

The **log of tape A** and the **log
of tape B **show what happened minute by minute during our two sessions.
The **video clips** provide glimpses into the action
at various points. Each clip is accompanied by a transcription. An explanation
of the **transcription conventions** is
available.

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