Is it Magic? De-mystifying the Foldscope

Recently in a workshop we probed into students’ curiosity related with their experiences with Foldscopes. One particular question, asked by a student of Grade 9, sparked a lively discussion in the workshop. The question was simple yet striking: “Is there any magic in the Foldscope?“, the student asked. She was perhaps curious to know how such a simple, inexpensive, small paper-folded device is able to magnify as much as a heavy and expensive compound microscope. Another student, from Grade 8, was more specific: “What is the lens used in the Foldscope and how can we make our own Foldscope?” We realised there was a sense of mystery among the students regarding the mechanism of Foldscopes. Their understanding of simple and compound microscopes did not gel with their Foldscope experiences.

Starting with how Leeuwenhoeck observed the details of cells and even bacteria using a single lens and a well designed platform, we found ourselves harking back to concave and convex lenses, real and virtual images, the critical parameter of distance of object from the lens (comparing with a spoon as a mirror), diagrams to explain that, ‘more the curvature of a convex lens, larger is the image’, and the challenges of working with a spherical, or ball lens. Parts of the compound microscope were shown that are anologous to the Foldscope — the slide stage with slide slot and coarse to fine adjustment with the focus ramp.

Discussing the mechanism of Foldscope, comparing with a compound microscope

That’s when students realised that their Foldscope consists of only one ball lens with magnification of 130X. There was wonder on their faces after checking their Foldscopes, realising that it is an engineering innovation by the inventors (Manu and Jim) to design the accurate folding of the Foldscope to hold the slide, move it and then bring the lens close to the sample to obtain clear magnified images, comparable to a compound microscope.

Students checking the lens in their Foldscopes

While the Foldscope was being demystified, one of the teachers demonstrated an innovative technique, to attach the lens of a laser pointer to a cell phone camera with a hairclip, which she found on YouTube. We observed the epidermal layer of a leaf using this hairpin microscope and clearly saw the cells and the stomata!! It was an exciting moment for all of us and especially for the students, who now felt more connected to the amazing magnification possibilities of single small lenses.

The hairpin-laser pointer lens microscope
Students with their Foldscopes

Thanks to the volunteers, teachers and students of TSWREIS.


Debashree, Ashalatha, Anu, Chandrika and Jayashree

6 Comments Add yours

  1. Manu Prakash says:

    Dear Debashree, Ashalatha, Anu, Chandrika and Jayashree,

    It’s so wonderful and heart warming to read this exchange. I see this often in my conversations – and one of the reason we insist sometimes that students fold a foldscope is to demystify it. But your description and conversation is just so marvelous.

    Another big news – in coming months, we will be releasing a “Foldscope inventors kit” which will provide all the key raw materials, abundance of lenses, magnets and paper – but a blank slate for students to invent their own versions of how to configure these components to build new optical instruments. This is to combine the engineering passion with biological curiosity. This is in the works – and as soon as I have the first kit in place; I will send several for you to test with your local groups.

    You continue to inspire and amaze everyone in the community. A lot more will follow this year with announcement of Foldscope Fellows program first based in India – and a new India foldscope manufacturing plant we are putting together to remove the bottleneck associated with number of units available.

    This is a busy year – I look forward to meeting you in person in near future.


    1. Akib says:

      What an exciting news! Can I have more information about it?

      1. Manu Prakash says:

        More in the planning. We will plan formal announcements within a month.

  2. Puchina says:

    Wow, that’s very exciting about using the laser pointer lens? Did you take any pictures with and without the extra lens?

  3. Tulasi Mastanamma says:

    Kids really enjoying and its an amazing experience of learning and wondering together.
    Its a great news Manu Prakash and we are waiting for that

  4. Jim says:

    The inventor’s kit is a great idea. I just received the Deluxe Individual Kit, assembled it, and have viewed one of the slides on my smartphone. Great job, you guys. The coloring of the parts really helps. I had a little trouble identifying the double-stick tabs that are shown in Step 4 of the assembly instructions. (Instructions are very good, too!) Maybe if the drawing of the stickers in that step is not grey, but some other color, it would help. Also I didn’t realize that the lens includes one of the couplers and they can be separated. I have a second lens with a coupler and do not know if it was included by mistake or has some other use. But, I’ll see if it can add it to my smartphone to increase the magnification. The final product can be stored in metal box that held the parts; that’s great, too. (It’s much more compact than a microscope, so shipping, storage and transport will be easier.) I have grand kids and neighbors to show this to and may give it away, but do not want to part with it yet. I’m 77 years old! Thanks to everyone. I can see that a great deal of thought when into the construction and hope the impact continues to spread. Regards, Jim in Smithfield, Virginia, USA.
    P.S. Great website, too!

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