Foldscope Challenges – Building Skills and Encouraging Exploration

Microscopy transports us to almost another world entirely – in this “alternate” reality, we find so much that is new. But like traveling to any place, the experience can be both thrilling and overwhelming. No matter how many guide books you read or phrase books you keep in your back pocket, there are no hard and fast rules for exploring a new place – you simply have to go out and do it, letting your own curiosity and instincts lead the way.

Using the Foldscope, and discovering the wonders of the microscopic world, is similar. There are no rules, and no one curriculum when it comes to introducing the Foldscope to students. However, there are skills that are useful for those travelling in the microscopic world. These skills can’t be imparted just through reading, but need to be earned through practice. In service of this, I have crafted a small set of “Foldscope Challenges,” designed as a training ground for Microcosmos explorers. Please feel free to borrow or adapt these for your own students…


Dear Microcosmos Explorer,

The following challenges are provided for you to build skills with using the Foldscope. Like all microscopes, Foldscope requires practice to get the best possible results. The challenges increase in difficulty and are all accomplishable, but you may not nail them on your first try – I definitely did not! Set aside at least a few hours for each challenge.

These will give you a sense of some of the beautiful and interesting things you can see with the Foldscope. They are not step-by-step guides because they are intended to get you thinking and tinkering.

However, you have resources if you get stuck! In real life science, there is no “solution key,” but by going to, you can find posts from global Foldscope users on a wide variety of topics. Try searching for keywords to find posts that can help you with a given challenge (e.g. “cheek cells”).

Within these posts you can find precious tips – use the comments section to find more info and to ask a question yourself. The Foldscope community is very friendly and open to everyone, especially those new to science and microscopy! The more you reach out, the more your skills will evolve, and more and more wonders of the microscopic world will be shown to you.

Challenge #1: View A Flower Petal


Flowers are beautiful when unmagnified, but the Foldscope puts their beauty on display at the microscopic scale, showing the individual cells that make up a petal.

To think about/tinker with…

  • Foldscope can be used with a number of light sources, including the sun, a lamp, and the provided LED. Generally, the best images come from bright and even Try all the light sources you have available and see what works best for you. If using a lamp, try changing the angle between the lamp and the Foldscope to get different types of images.
  • Microscopy requires light to pass through the sample you are looking at, so the lens can focus that light into your eye. Samples that are too thick or opaque will not work well with most microscopes, including Foldscope. In addition to your flower petal, try leaves with different thicknesses…what works and what does not?

Challenge #2: View Your Own Cells


It’s amazing to think that the human body, with all its complexity, is a collection of trillions of tiny cells. Each cell performs a special function to keep you alive. Try to view your own cheek cells (from the inside of your cheek) by collecting them with a Q-tip or toothpick.

To think about/tinker with…

  • Microscope images can be fuzzy or sharp depending on whether they are in focus. Focusing requires you to change the distance between the lens and the sample until you get a sharp image. Since cheek cells are quite thin, they will be hard to see without the right focus. For one strategy on “focus-locking,” read the following post:
  • Many interesting samples in microscopy are colorless. To see them more vividly, different stains can be used. A commonly used stain with cheek cells is methylene blue, but it is not essential to see the cells.

Challenge #3: View A Tiny Pond Creature


Perhaps the most fun use of the Foldscope is to observe the strange lives of tiny creatures that you never even knew existed. Pond water is often teeming with microscopic life, including ciliates, flagellates, amoebae, and algae. Collect water from a pond or puddle and find a living, moving creature inside.

To think about/tinker with…

  • A “wet mount” – a liquid sample – is a common technique in microscopy, but may take a few tries to perfect. You will want to sandwich your liquid drop between stickers, tape, or glass, without crushing any creatures in the drop.
  • Sometimes microscopic creatures are sparse. Think about how you might increase the number of creatures per drop, either by a) concentrating the specimens, or b) feeding them to encourage growth.

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