Ramps – Reflections

Why is this science?

The students have a shared goal, to make sense of the “anomaly,” and they  pursue it in several ways we see as scientific:

  • connecting and comparing with their understandings of other phenomena, such as a hydroplaning Prius or a bicycle colliding with a cardboard box;
  • building on each others’ ideas, such as Max adding to Emilia’s bowling ball on a pillow idea by introducing a ramp to the situation;
  • holding each other accountable for consistency, such as Kapp using an extreme case of a parachute to critique Ellie’s statement that surface friction matters more than air friction;
  • evaluating each others’ experiments when they question the WD-40 group’s procedure and arguing about whether it matters that they didn’t have a real “control”;
  • \looking for patterns in data and trying to decide if weight group’s data is a trend or just noise. For example, Isaac thinks a difference in friction might be too small to be noticable, but Sarah thinks the outlier in the data cannot be ignored, a point she argues because Isaac’s suggestion is inconsistent with their current model of how friction operates.

Throughout, the students are thinking about mechanism, including about how more weight or a softer surface ought to mean more friction, how a heavier object would have more inertia, how dust particles might affect the cart’s motion.

What contributed?


This episode is the conclusion of a multi-day investigation of an “anomaly graph” (named by a student group) coming out of an otherwise standard lab activity. Finding the reason for the anomaly graph became the class curriculum for several days.

At one level, the students had a shared sense of what question we were trying to answer. For example, when Ellie made a comment that moved away from this question (“Surface friction affects the cart more than air friction”), the rest of the class brings the conversation back to the question they cared about (Does friction explain the anomaly graph?).

At another level, each group had a sense of ownership and responsibility for their experiments: because each group created its own unique experiment, students had to explain their own experiment and evaluate each others’ experiments to determine if and how they provided evidence for the question at hand.


Not only did students perform their own unique classroom experiments, they also drew on everyday experiences outside of the classroom and intuitive senses of mechanism.  For example, David P shared his experiences with his Prius hydroplaning, and Marka appealed to students’ intuition with a hypothetical example of running into a cardboard box on a bicycle.


The teacher framed this discussion as consensus building (“Can we conclude anything?” “Do you all agree with that?” “Can you repeat that for everyone?”), and students had ambiguous experimental data they had to resolve. She also supported framing the goal as seeking coherence, including with evidence and ideas (asking for evidence, “what evidence makes you say that?” “Well, did it get much better…?” “How does the… weight group fit in?”)


The students’ experiments, experiences, and senses of mechanism were often at odds with each other. They recognized that, and it concerned them, for example Isaac and Sarah highlighted a discrepancy between their results and intuition (“I feel like it still should increase the difference in slopes but it didn’t.”) The shared goal or norm was to arrive at a conclusion/understanding of the anomaly graph that would cohere. They had to work to understand each others’ experiments and ideas to determine how they fit into to their tentative friction explanation for the anomaly graph.


There is a positive atmosphere and social comfort present in this discussion – students are sharing ideas freely and responding to each other, often without raising their hand. Students feel comfortable to joke and laugh, and this laughter seems to be generative – students riff off each other and build on each others’ ideas, and they use humor to manage tension.