In what patterns can a strand of hair go grey? Low/high mag pics

Human HairHuman Hair 400Xloss of pigment 400x  loss of pigment 400x 400x lighter hair

After struggling to record high mag lens work, I decided that I might be simply misunderstanding what I see through the high mag lens.  Color saturation, light, and pattern are hard to interpret when we are used to our eyes alone or a low mag lens.  Reminds me of the concept someone else shared, that, for tiny organisms, moving through water is like swimming through molasses (for us).  Are fewer photons present because of the smaller space?  I guess yes, but have an understanding of light and intensity on the level of a child seeing for the first time.  Maybe my lens is just dirty!  😉  I’ve included the low mag image along with 4 high mag images of the same paper slide with Foldscope tape front and back.  Will be letting students mess with high mag iPad photography next week.  They were highly successful at viewing through the LED/high mag setup, and are ready to go!

2 Comments Add yours

  1. Manu Prakash says:

    Couple of comments:
    1) Yes, lenses do get dirty. What you want to do is take a cloth (not a paper napkin since it has so many strands); and just take water (NO alcohol or other cleaner since they might melt the plastic frame, black tape) and rub both sides. Let the lens dry before reusing. Simple. Damp cloth and you are done.
    2) As magnifications get higher and higher, the back focal length of the lens gets smaller. So what all that means is you need to come closer to the object you want to see. If you are using a sample that has some thick cover slip, you can not fundamentally come closer than the thickness of the cover slip (because of the glass). So you want to use thin cover slip or even no cover slip. Just use the tape – that should work well.
    3) At higher magnification, less light can pass through (since the aperture through which the light comes is smaller, and so images are a little darker. But that should not matter that much.

    My guess is #2 is the problem. Play with it more with objects you have imaged at low mag. Starting and perfecting your technique with low mag is both important and very very useful.

    Good luck. Can’t wait to see what you discover.

    cheers
    manu

  2. Thanks, Manu,

    I’ll take the above advice and then turn my middle school students loose with the iPad and high mag setup next week. They will be able to show me what is possible – they have engaged with Foldscope as naturally as a toddler with a set of pots and pans and a wooden spoon!

    My best,

    Kate

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