Turn your iPhone into a portable microscope. Should also work for any other smartphone. All I'm doing here is placing a small lens right in front of the iPhone camera. Keep it place with some foam tape and start looking at everything! Really big!
I read about this technique here where it was used to look at stool samples on slides (fun!), but I mostly used it to look at color slides and other flat things. Below is a video of moving a slide photo of a building in front of the lens.
Step 1: Materials
Stuff to get
Step 2: Make lens holder
This is pretty simple. The lens needs top be held in place and that's easier with a round hole in the foam tape. My tape is too thin on its own so I doubled it up and then used a pen as a hole punch. Place the tape on some cardboard and keep hitting until you go through. It's easier if you do each piece of tape separately, but you can try both at once if you want.
With the hole made, place the lens inside and put a couple small pieces of scrap plastic on the side so the tape won't stick to what you put up against it.
And that's it.
Step 3: Look at stuff
Look at things! Grab some stuff that can lay flat in front of the lens and see how it looks much bigger. Here I'm using my fingers to spread a leaf to keep it taut. You can also tape items to a clear piece of plastic and look at that.
The last picture is of my fingerprint. The line in the middle is one of the grooves of my fingers.