Work Sample & Commentary: Mechanical Nut
The task
After a unit on motion and forces, students were asked to move a mechanical nut in a horizontal direction as far as possible without directly rolling, throwing, pushing, or sliding the nut itself. The students were given limited materials (cardboard tube, small plastic container with cap, 70 cm of ramp, cotton, small pebbles, and meter sticks) to accomplish the task. Additional “challenge” tasks were assigned, such as moving the nut exactly one meter. After recording observations and results of various experiments, the students were required to complete a written report including the following sections: title, purpose (hypothesis), materials, procedure, results, and conclusion.

Circumstances of performance
This sample of student work was produced under the following conditions:
alone in a group
in class as homework
with teacher feedback with peer feedback
timed opportunity for revision

This work sample illustrates a standard-setting performance for the following parts of the standards:
b Physical Sciences Concepts: Motions and forces.
b Scientific Thinking: Use concepts from Science Standards 1 to 4.
e Scientific Thinking: Identify problems; propose and implement solutions; and evaluate the accuracy, design, and outcomes of investigations.
f Scientific Thinking: Work individually and in teams.
e Scientific Communication: Communicate in a form suited to the purpose and the audience.



What the work shows
b Physical Sciences Concepts: The student produces evidence that demonstrates understanding of motions and forces, such as inertia and the net effects of balanced and unbalanced forces.
In the results, the students identify forces acting in this system, and describe the effects of those forces. The students correctly state that gravity pulls the mechanical nut down, affecting its motion. The students correctly identify how friction changes the motion of the nut.
The students’ conclusion correctly describes how different forces affect the movement of the mechanical nut. The students describe how balanced and unbalanced forces act upon the nut in terms of changes in direction and/or speed.

b Scientific Thinking: The student uses concepts from Science Standards 1 to 4 to explain a variety of observations and phenomena.
The students correctly identify and describe the effects of friction on motion.
The students correctly identify and describe the effects of gravity on the mechanical nut.

e Scientific Thinking: The student identifies problems; proposes and implements solutions; and evaluates the accuracy, design, and outcomes of investigation.
The students evaluate the successful outcomes of their procedural designs, and provide insight into the reasoning behind specific details of each procedure.
The students identify five problems (numbered by the students themselves as A through E) and design and implement a procedure that solves each problem.

f Scientific Thinking: The student works individually and in teams to collect and share information and ideas.
In the results, the student who recorded for the team states overtly that the work was done as a team. Phrasing such as “My partner and I…” and “…we used…” makes it clear that the students worked cooperatively throughout the development of experiments and presentations.
The student prefaces the activities with a statement that the procedure is being carried out in partnership with another student.

e Scientific Communication: The student communicates in a form suited to the purpose and the audience, such as by writing instructions that others can follow….
The students presented a written report that pairs each problem with a plan and a diagram of the set-up. Three plans are clear, concise and accurate representations of the procedures, and they meet the standard. (The remaining two pairs require some minor clarification for replication by other students.) The students created a report that demonstrates an organized structure appropriate to the purpose, audience and context, and excludes extraneous and inappropriate information.