Abigail B. Roberts 
Using Lenses [PDF ebook] 

Observing objects closely is an important part of being a scientist. That’s why lenses are so important in the laboratory and in the science classroom. Young scientists may be surprised to learn that they’ve probably already used lenses-in the form of a magnifying glass. This tool and others, such as microscopes, help scientists see details of objects up close. This invaluable book introduces lenses and the concept of optics in an easy to understand way and encourages readers to experiment with lenses themselves!