Science Buddies: "Ask an Expert"

I have created a cell phone microscope and I'm having trouble figuring out a way to collect data. How can I collect data and graph it?

The usual way is to place something of known size in the field and see how big that is, and compare that to the unknown item you want to measure. The best thing would be a 'stage micrometer', a microscope slide with a teeny ruler etched into it. If you snap a picture of that and determine the ratio of pixels per uM, then snap a picture of some unknown, you can calculate the size of the unknown pretty easily.

You can find stage micrometers all over the internet, or your school may have one you can borrow.