There are very few monochromats (not able to distinguish any colours at all), but they do exist.
Most “color-blind” humans are red-green color blind because they lack one of the three color receptors. They can distinguish other colors. As Canadjun says, there are a few monochromats. As I mentioned above, most mammals are color-blind in this way: they are dichromats, having only two color receptors, and thus red-green color blind. Almost all red-green color blind people are male, because the mutation is sex-linked (on the X-chromosome).
Dug out my “Sensation and Perception” textbook.
Monochromatism (not seeing any colours) occurs about once in every 100,000 people.
There are three different types of dichromats (what people usually think of as colour blindness), depending on where the peaks in colour sensitivity are. Protanopia affects about 1% of males and 0.02% of females. Deuteranopia affects about 1% of males and 0.01% of females. Tritanopia affects about 0.002% of males and 0.001% of females. So, DrDeth’s suggestion of getting a colour-blind friend to help check the experiment is problematic - what kind of colour-blindness?
Just to add another tidbit, there is such a thing as an anomalous trichromat who does have the three colour receptors but not with the usual sensitivities; they have difficulties distinguishing certain wavelengths that are close together (my textbook doesn’t provide stats on the occurrence of anomalous trichromats).
Whatshername,
Go here to find out more information on Science Fair Projects:
Also the nice librarians there can help you out if you need some more information.
Hear, hear!! As a science teacher, I HATE science fairs for all of the reasons I see in the OP. He/she isn’t curious about anything. He/she isn’t trying to investigate a question. He/she doesn’t care about the answer, just the outcome of the competition. Where’s the scientific inquiry in that? Somebody else asked the question, there’s a cookbook way of finding the answer, and viola, another kid is bored out of their skull with science.
If you want an interesting QUESTION to pose and investigate, how about looking into the relationship between the amount and variation of coloration in a species and what that might say about the species’ ability to *see *color. Are mammals mostly brown, black and gray because most mammals don’t see in color? Are brightly colored birds seeing those bright colors in other birds? Sounds like a more interesting question to me. The problem, of course, is that it doesn’t lend itself to a canned experiment. That’s another reason I hate science fairs. Okay, I done here. Carry on.
Thanks so much everybody!!! i’m going to use a bit of everybodys ideas. I don’t like science fair because my teacher only talks about (most of the class) science fair, not A and P… Thanks again everybody!!!
A random note. Long ago, a friend showed me something that suggested cats can see at least some colors. (I’ve since learned that they can indeed.)
He had two rubber-insulated wires, one black and one red. Whenever he waved the black wire around, the cat did nothing. The cat consistently played with the red one.
Not proof positive of color vision, of course. One might even argue it was the luminosity, not the color, at work. Still, maybe there’s a clue there for setting up a real experiment.
Does the OP really have to have a conclusion ready?
Because I was thinking that the suggestions here were pretty interesting in their own right. (That is, the experimental processes taken to weed out erors, and such.)
Given the time constraints (1 week), could a science project be presented as an ongoing experiment, with discussion including not just the ultimate outcome, but also the process itself?
(Indeed, I imagine that if a presenter looked thrilled and excited about their experiment, even if not quite complete enough for a Noble Prize in biology, the judges might subconsiously award “enthusiasm” merit points…)