- If possible, provide students time to visit the websites of various mints worldwide, and in particular the virtual tour of the U.S. Mint.
- Divide students into groups of 2-3 student "engineers," providing a set of materials per group.
- Explain that students must develop a system for sorting coins, just as engineers develop sorting systems for manufacturing and packaging facilities.
- Students meet, review provided materials and coin samples, and develop a plan for their system. They agree on materials they will need, write or draw their plan, and then present their plan to the class.
- Student groups next execute their plans. They may need to rethink their plan, add materials, or start over.
- The teacher or "engineering manager" will move from system to system and test the sorting "machine" using a bag with 10 of each coin.
- Teams record how many coins are correctly sorted into separate containers (boxes, bags, cups).
- Each student group evaluates the results, completes an evaluation/reflection worksheet, and presents their findings to the class.
Tips:
There are many ways to sort the coins. It's best to let the students come up with their own solutions which will also expose them to the processes of negotiation and teamwork -- all of which are part of the everyday life of an engineer.
A ramp may be used with holes just larger than each coin cut into a cardboard or wood base -- the smaller holes are at the top so that the smaller coins are sorted out first. In this method, the angle of the ramp will determine if the coins move down at a slow enough speed to be caught in the holes (too close to vertical will cause the coins to move too fast to be caught in the holes; too horizontal a slope will cause the coins to get caught and not move down).
Another method is using gravity by setting up a series of hanging plastic or paper plates, precut with holes for coins to fall through. In this system the larger coin holes will be in the top plates, with the smallest at the bottom. By shaking gently, or angling the plates so the coins fall from one to the next, the coins will sort themselves through.
