Several possible variations exist for this experiment, and students can do any or all of them. The first stage can be to establish the efficacy of the method. The separation of ink components depends both on the solvent and the paper. As a result the first part of the experiment is to try different kinds of paper and different solvents to determine which conditions give the best separation and are best able to distinguish among various different pens. The main preparation for this experiment is to obtain boxes of pens from different suppliers.
Students then determine which pen of the various possibilities was used to write the note.
In subsequent years, with a supply of dated pens, it becomes possible to devise experiments based on back-dating in similar fashion. The main point of this experiment is the composition of compounds, specifically oxides. This experiment teaches quantitative techniques, including titration if all parts are done. The determination of the composition of magnesium oxide is determined by careful weighing of the product of reaction of magnesium and oxygen from the air, while the titration part of the experiment is used to determine the composition of the superconductor. The statistical analysis of data is optional, but better students find it an enjoyable challenge to their quantitative skills.