Why do sheep never catch colds? It's because of their warm, woolly coats! This is just a joke of course, but there's a bit of truth to this tale. Hikers and mountain climbers generally wear clothing made of wool, because of wool's unique characteristics. It can absorb up to one-third of its weight in water, while still keeping the body warm. Invite your child to test this phenomenon by performing a wool and synthetic sock comparison!