Investigating Inks

Method:

Key:
A=Green highlighter
B=Purple highlighter
C=Black fineliner
D=Black permanent marker

  • To start with, draw a straight line in pencil near the bottom of a rectangular piece of filter paper (chromatography paper could be used instead).
  • Then, label A, B, C and D along the bottom before placing a dot of the corresponding ink (see key above) on the line above each letter.
  • Following this, roll the filter paper into a tube.
  • Next, place the filter paper in a glass with a small amount of water making sure it does not touch the sides and that the line is at the bottom of the glass.
  • Finally, observe as the water carries the ink up the filter paper.

Results:

Conclusion:

Ink A shows a yellowish green ink as well as a second ink of a slightly darker green. Meanwhile, ink B is a mixture of a purple and bright blue. This blue can also be seen in ink C. However, ink C shows more of this and has a greater variety of colours than ink B. These include a fiery orange, salmon pink, lilac and a light purple similar (but not identical) to that of B. Finally, D does not show any change and has stayed as the black ink.

The yellowish green in A is the least soluble in water (after the dyes in D) with the blue in B and C being the most. Meanwhile, ink B’s purple dye is the second most soluble in water with the purple in C being slightly more than the yellowish green. The fiery orange is the third most soluble followed by the salmon pink and lilac. Finally, D is insoluble. However, these results are with water as the solvent. If a different solvent had been used, D may have been soluble and the other inks may have shown very different results.

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