You have probably seen a gecko run straight up a window. Your first guess might be that its feet are sticky, like they have glue on them. The truth is far more interesting. Geckos and anoles climb using something called van der Waals forces. Here is the short version: when two things get extremely close together, so close that their molecules almost touch, they pull on each other a tiny bit. Normally that pull is too weak to notice. But a gecko's toe pads are covered in millions of tiny hairs, called setae (SEE-tee), and each hair splits at the end into hundreds of even tinier pads.
This lesson is part of Certified Junior Herpetologist. Enrollment is self-paced, with no deadline to finish (about 30 hours).
