Two euros

Two euros is a task for a small group. It is less a game than a challenge of group dynamics for the group. A group of five to ten players solves the problem. If there are more participants, they may take up the role as passive observers.

Material

 * A two-euro coin (or the like) is required.
 * In addition, the group should have at their disposal material that is not specified but typically available in seminar rooms/classrooms/holiday camps, such as paper, glue, pens, etc.)

Procedure
The procedure is quite basic. The group has to solve the following problem: "How much does a two-euro coin weigh (in grams)". The group has the entire material within the room at their disposal. Scales and the like are explicitly not allowed. The group should be creative and find a solution regarding how to measure the weight of the coin.

Of course, the correct solution of the problem is not important, but the approach to arriving at a result. The correct solution would be 8,50 g.