100 Physics Ideas in 100 Words

g CONTENTS

Introduction

We can think of physics as starting with astrology, several millennia ago. At a time when there was less light pollution to reduce the visibility of the stars in the night sky, people were more familiar with the pattern of the constellations. They knew that certain stars were only visible at particular seasons. They observed that some stars seemed different, changing their positions against the pattern of the fixed stars – these were the planets. The appearance of the Moon changed from night to night. Occasionally, people observed eclipses of the Sun and Moon.

Astrologers learned to record these changing patterns, to measure the positions of the heavenly bodies and to predict events in the night sky. They did this ...