Describe an experiment, using a labelled diagram in the box provided, to investigate the composition of inks in markers containing water-soluble inks, to see if they are a single-colour ink or a mixture of coloured inks - Junior Cycle Science - Question c - 2008

To investigate the composition of inks in markers, you can perform paper chromatography.

Materials Needed:

• Chromatography (filter) paper
• Marker pens with the inks to be tested
• Water
• A beaker

Steps:

1. Preparation of Paper: Cut a strip of filter paper about 2 cm wide and 10 cm long.
2. Applying the Ink: Use the marker to place a small dot of ink about 2 cm from the bottom of the paper strip.
3. Setting up the Experiment: Fill a beaker with about 1 cm of water. Ensure that the ink dot does not touch the water level.
4. Chromatography Process: Place the filter paper strip into the beaker so that the bottom tip touches the water. The water will rise up the paper via capillary action.
5. Observation: Allow the water to travel up the paper for several minutes until the ink begins to spread.
6. Results Interpretation: Remove the paper once the water has moved a sufficient distance (about 5 cm).
7. Labelled Diagram: Include a labelled diagram showcasing the setup with the chromatography paper, ink spot, and water level.

Conclusion:

• If only one colour spreads from the ink dot, the marker contains a single-colour ink.
• If multiple colours emerge and separate, it indicates a mixture of coloured inks.