Here's a fun one that a student brought to me recently: After you pour a cup
of soda, watch the bubbles that rise to the top (you have to wait until the
initial foam dies down). The individual bubbles that make it to the top will
often times race toward oneanother. I had never noticed this before but it
really does happen. There appears to be something at work other than
random-chance collisions. Why are the bubbles drawn to oneanother? If
this leads to some giant scientific discovery, my student has dibs on naming
it the Geoff Phenomenon. Thanks.