TOPS #42 Focus-Pocus

The title of this book sounds like magic. Just gather the simple materials, sprinkle with water, and shout ""Focus Pocus!"" You'll get a canning-ring projector, a washer-lens reducer, a beverage-bottle magnifier and microscope, and a soda-straw superscope. Keep stirring with hand lenses (you can order these from TOPS) and you'll brew up a lens platform that traces the bent path of refracting light rays, and a working mechanical eye. A meter-stick protractor connects these marvelous learning systems to solid math as your students measure angular size, graph visual acuity, and explore the inverse relationship between distance and apparent size.