“The Foldscope is an ultra-low cost microscope made from common materials such as paper.” It could cost less than one dollar to produce, and there maybe be a Kickstarter coming for it soon.
I love it when a TED talk becomes reality. I saw this a couple years back and forgot about it until recently. Many more details in this research article. The idea and design of this thing are genius. From one piece of paper, plus a lens and battery to power an LED (shown below in black):
It constructs and looks something like this:
And from the side operates something like this:
My kids are at an age when things like germs and bacteria are being discussed, due to their persistent asking of ‘why’ about everything, so to help explain when things get too small for them to see, this will be an incredible help. At least, more of a help than showing them Powers of Ten by Charles and Ray Eames, which was entertaining enough, but possibly a little too abstracted for having to explain what a light year was. Fun to try though. Give it a go next time you have access to a four year old.