Tom Gordon from the School of Physics at University of Sydney is running a project to find how accurately we can measure time with drops of wax from a birthday candle. Somewhat self-referentially, the project also aims to try a collaborative citizen science and science communication project using online tools and mobile devices. Gordon says nothing similar has been done before which is really surprising, and might well just be a matter of definition given the use of phones and tablets in the reporting of earthquakes, animal sightings, and so on.
Anyway, to participate you just need to use your device to measure how many drops of wax fall from a lighted candle in sixty seconds and report that back. This would be a nice experiment to try with the kids or in a class.
For the full instructions and a form to report your results see here.