I build a home-made spectrometer made using a webcam and inexpensive hardware-store pieces, and associated analysis code, to detect impurities and contaminants in a liquid sample. More detailed description here.
I'm showing this at the Vancouver Mini Maker Faire June 6-7, 2015.
On the surface of the sun, there are cellular patterns of different scales. I worked on supergranulation, which has cells with diameters on the order of 10,000 km. These cells had been observed to be behaving as waves, and further to be moving faster than the surface plasma of the sun. I modelled their dynamics to try to explain what causes this behaviour.
You can see my thesis here, if, for some reason, you want that level of detail.