Simple Slopes

A slope may not look much like a machine – but that is exactly what it is! Useful slopes crop up all over the place. They may be blindingly obvious, like a ramp, or frankly surprising, like a door key. So how do slopes make a zip fastener unzip? Where are the slopes on a drill or a pair of scissors? These questions, and many more, are answered with simple explanations and an originality of approach which should persuade even the most reluctant scientist that physics can be fun.