August’s CAMI meeting began with the following story:
You are brought to a crime scene. You are told that a thief just made off with a bag full of diamonds, escaping on a bicycle. You come across the following pair of bicycle tracks in the snow, no doubt made by the fleeing thief. But which way did the thief go?
The screens around the room projected this image and the question was posed: Just by looking at the tracks, can you determine which way the bike went?
With two real bikes in the room, we had an opportunity not only to look at some tracks on the screen but to create some tracks of our own. Before addressing the question, we decided to make some authentic bike tracks. A few participants rolled out some handy butcher paper and taped it to the ground while others colored the wheels of the bikes, the back tire in blue and the front tire in red. We then rolled the bike across the paper, making turns to simulate riding a bike across the snow.
After we produced the bike tracks, we split into four groups of two to begin thinking about the question: which way did the bike go?
Each pair thought about the problem differently and used unique strategies to answer questions they were curious about. After a fun hour of discovery, it was time for the groups to share.
Sophie and Janet began by sharing their ideas to generate bicycle tracks using a few markers and their hands. They discussed their method of creating tracks going in both directions and comparing the two.
Next was Usha and Felice who used more paper and chalk with the bike to create strange sets of tracks. They made the bike take very sharp “V turns” and examined what happened with the back tire. They also posed some new and interesting questions that stemmed from that experiment.
Greg and Mark followed by sharing their strategy of examining the length of the bicycle and how that connects to the tracks left in both directions.
And finally, Kevin and Ramon shared their work, shocking the rest by trying to contradict an assumption that most of us had made about which tire was which!
But did we answer the question? Which way did the bike go? Some pairs seemed to have found themselves an answer while others just encountered more questions to think about.
Some other questions that came up included:
Can you generate the back tire’s track if you are given the front tire track? Is there just one possibility? Infinite possibilities?
What do inflection points in the back tire’s track mean about the bike? How do they relate to what happens with the front tire?
What happens when we think about the area between the two tracks?
What happens when we ride the bike in a circle? What about the area between those tracks?
There were many more questions posed and very few answers! But we all certainly had plenty to think about on the train ride (or bike ride) home.
