Notes Teams of no more than three students are best for getting all team members involved. Most students try to force as much material into the mold as possible, in spite of the warning to adhere to the specified dimensions. Explaining up front that any composite that does not fit into the holder will be trimmed with a pocket knife until it does fit helps keep those instances down to a minimum. Be sure to point out that although it doesn't matter whether they pick foil or plastic wrap to line the mold, it is very important that the liner not have any tears in it. For example, if a team tears the foil while poking it into the mold, they will need to reline the mold or the composite will stick.
Most students have difficulty understanding the necessity of cohesion in the composite.
Unless it is explained that the strength of the composite derives from how the materials are combined together, almost all of the teams construct a composite with separate layers - the key word here being separate. The usual tactic is to fold the paper to the exact length and width dimensions of the mold and place it in the middle of the composite between two layers of cement. With the cement on either side unable to bond with the other, the composite tends to pull apart like an oreo cookie. The cement needs to be thoroughly mixed. Be sure not to leave dry powder at the bottom of the container.