Try this simple test to see if different types of ink are chemically the same.

You will need: felt pens; paper towel; scissors; water.

1. Collect several different types of black felt pens (permanent markers do not work). For the experiment, use two of each type of black pen.

2. Cut separate strips of paper towel, each about 2cm wide - two strips for each pen.

3. Mark each strip of paper towel with a dot and record in your book, which pen you used to make the dot.

4. Using one strip at a time, dip each strip in the water. Dip the paper towel to just below the dot, making sure that the dot stays above the water. Allow the water to soak up the strip and observe what happens to the ink.

5. When all of the strips have been dipped into the water, see if you can match up the marks made by each type of pen. Check if what you matched from observations was the same as the results for your record of the pens.