Michael, You can graph several things for your experiment. Use days along the x axis (horizontal) and several different variables on the y-axis (vertical) including (a) color intensity, (b) browning of petals, (c) overall appearance or freshness, and (d) lost petals. You can use lost petals for flowers that may drop petals, like roses. Carnations probably won’t drop any petals. I would suggest you develop some type of scale, or, if you have access to a digital camera, take a close-up photo each day. You could use our observation sheet along with Experiment #1 for some additional guidance.
If you take the photos with a newspaper date heading or just a 3×5 card with the date, you can then do a real “show and tell.” It will also give you an opportunity to adjust a scale, knowing how brown the petal tips will become and/or how much dye will be absorbed. A scale can go from 0 (no petal tip browning) or (no dye taken up) to 10 (all brown petals ) or (solid color from dye). You likely will see results then that go from 0 to 5 or 7 (probably will take too long to get to 10). I wish you much success. - Bridget