[3ACTS] Double Sunglasses

My video Target Tint was taking a beating over on 101questions with well over 50% skips. But the overall concept seemed solid to me. What happens when you apply multiple layers of tint? My guess is that people watched that video and figured the answer was a matter of simple division when, in fact, tint is more complicated and more interesting than that. If you wear two sunglasses with 50% tint each, for instance, are you then blind? So I reshot it and the result is now humming along at 90% perplexity as of this writing. Raise your hand if you dig the revise-and-resubmit cycle of teaching.

Here’s the task page.

I'm Dan and this is my blog. I'm a former high school math teacher and current head of teaching at Desmos. He / him. More here.


  1. Hand raised high over here!
    I want to get a few more views of my Rock Paper Scissors – Act 1 and see if it’s worth a reshoot. I thought it was a slam dunk, but seems to have reached a stagger.
    I’ll admit, I found the sunglasses version more appealing than the Target Tint. Appealing to perplexity that is. Plus, we get to see you sport those lovely oversized beauties. :P All in the name of learning!

  2. Nice glasses, Elton….

    This video reminds me of a project a student conducted in an AP Stats class of mine a few years ago. The student was interested in determining if Oxy Clean was better than Tide at removing stains, and cut apart clean t-shirts, smeared them with ketchup and chocolate sauce (blood was disallowed), and cleaned them. This resulted in about 50 swatches of cloth with various degree of stain-li-ness. The problem was that, while we understood that some shirts “looked” cleaner, how could we measure it?

    The same idea applies here. A student may “know” that the result will be darker, but how to we measure darkness? It would be interesting to see what kids come up with for conducting such a measurement. How exactly do we measure “tint”? How do we know that something has 50%, 75%, 5% tint, etc?

  3. You might be able to put the pieces on a scanner, and get a number for the color of the dirt, and the size of it. The scanner can usually be set to not automatically change contrast.
    In the olden days of cameras, there used to be an accessory called a reflectance meter. You might find one in an old camera shop. You could set up a light system and then measure the reflectance.
    Another suggestion, if you happen to know a medical person, is to use a finger oxygen sensor. You might have to put some sort of blocker in until you get a reading, but you could play around until the stains gave you a reading change. One wavelength, so more standardized.
    There are companies that make colorimeters, but they probably won’t give you one.

  4. I’m pretty sure my whole teaching career has been “revise-and-resubmit.” But that is the great thing about teaching: you can reinvent yourself every year, every day, every period. It is one of the reasons I love being a teacher. It sure isn’t the paycheck . . . but I am not complaining!

  5. I love the new version, so my hand is raised super high! I am still wondering if there is any way that we can have these re-submissions chronicled rather than just nuking them from the server?

    So that it resubmits it into the list, and we can see the development of the task. Like a portfolio of task creation. Too complicated? You’re probably right. I just love seeing the creative thought that goes behind these remixes.

  6. I like this video project. I can see it fitting in as a great hook when we start looking at exponential functions and exponential decay.