Scoot across the floor in a device similar to a hovercraft. Drill a hole in ice using hot water. Learn how to photograph the transit of Venus in June, when the planet will appear to glide across the sun. UW-Madison?s Science Expeditions on Saturday will feature five major open houses, six science spectaculars, more than 20 venues and 60 hands-on exploration stations ? the largest collection of activities ever for the 10th annual event.