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by Dave
and Michelle Youngs.
This month the Puzzle Corner activity utilizes concepts from one of
the most recent fields in mathematics- topology. Topology is the study of geometric
properties that are not affected by changes in size and shape. This includes
the study of knots, inside and outside, networks, and the transformation of
shapes and surfaces.
Linking Loops is a classic disentanglement puzzle that has been around
for many years. If any of your students are familiar with it and know how to
solve it, be sure to ask them not to give away the answer to their classmates.
Students will need to work in pairs for this activity. It is best if you pair boys with boys and girls with girls. Each student will need a piece of string about 150 cm long. The string should be at least the thickness of kite string. Students will tie a loop at both ends of their string through which they will slip their hands. These loops should fit loosely. Check to see that all students are properly connected to their partners, as shown in the diagram on the student sheet.
At first, this puzzle tends to be fairly difficult for students, and they
will likely spend a lot of time going between legs and over heads in attempts
to separate themselves. At some point, however, students should realize that
no amount of acrobatics or contortions will separate them from their partners,
and begin to think about the problem logically. You will probably need to spread
this activity over the course of a week or more to give all pairs a chance to
discover the solution for themselves. Encourage students who do discover the
solution to keep it a secret so that each group can experience the satisfaction
of solving the puzzle.
Worksheet
| PDF version (135K)
I hope you and your students have fun as you try to discover the solution
to this topological challenge. In fact, you may want to bring a camera on the
day that you assign this puzzle to capture some of the interesting and often
humorous positions that students will get themselves into. We'll have the solution
for you next month, along with another Puzzle Corner activity. |
