Robert S. answered • 09/17/20
PhD in Chemistry with industrial R&D and teaching experience
Hi, Michel,
Interesting problem. Unless you have a good measurement system for light and color, the best alternative would be a visual comparison standard. For example, if you are testing a certain type of stain, such as blueberries, you could make a test strip with differing levels of blueberry stain and use it for a visual comparison. Litmus paper is often used to measure pH of a solution, based on the color change. In your situation, a similar visual conclusion can be made if you have several comparison stains that you rank from, for example, from 1 to 10. Have these color intensity standards next to the item you are measuring, and judge where it stands.
You might consider taking a digital photo of the stain alongside the standard strip. Others could then assess the accuracy of your measurements. The standard strip would be best if made of the same material you are testing (e.g., fabrics).
Best of all, you can name your new scale and give it your choice of units. Label it the "International Michel Stain Assessment Scale," and give it units of "michels." "That stain was rated at 9 michels."
[Note: a successful scientist is always aware of the acronym that will evolve from his or her idea and name. The IMSAS above is OK, but a little long. Alternatives might be explored: Michel Assessment Stain Scale (MASS), or Michhel's International Stain Scale (MISS). You get the idea.]
This technique is susceptible to bias, however. It requires judgement, and can therefore be influenced by the researcher's proclivity to thinking their solution is best. I know you wouldn't do that, but a digital photo of the test stain next to the standard is good evidence of your unbiased observation, for the ACME company lawyer whose stain remover you just dissed.
The human senses are remarkably good at perceiving differences. Our sense of smell, for example, allows one to discern low numbers of certain molecules because of their impact on our receptors. Dogs are even better in the nose department. Have you even been in a noisy room and heard your name mentioned on the other side? We can't hear as well as many animals, but our brains help discern certain sounds that are important to us.
Good luck on your science fair! The judges might get a kick out of a brand new, and named, stain measurement system. Be creative, and document well. Have your written hypothesis completed before you start, and work hard to disprove it. Yes, I said disprove. A theory is "proven" by both positive and negative results. If your hypothesis is "the world is not flat, it is a sphere," one could find a lot of evidence that would seem to prove that. It is a statement such as, "If the world is a sphere, then one can walk anywhere in the world and not fall off the edge" that helps prove a theory. If you then walk anywhere in the world, and fall off, the theory is wrong. Don't forget to tell us, before you fall.
The judges will look for a written protocol: Exactly how are the experiments done? Display the hypothesis and protocol prominently on your poster, along with a succinct conclusion. (e.g., The data demonstrate that ACME's stain removal product and procedure are often inferior to just hot water (over 70oF) and elbow grease (metric term for working hard).
Bob
