Simple Slopes - How Things Work Author:Andrew Dunn Each title in this series takes one simple scientific principle as a basis for explaining the workings of a selection of everyday gadgets and machines. The illustrations aim to de-mystify the scientific theory and expose the workings of each machine. Focusing on simple slopes, this book explains the principle of inclined planes and describes the... more » many everyday uses of this most basic of machines - for cutting (scissors and ploughs), lifting (ramps, jacks), fastening (zips, keys) and drilling.« less