4. Wonders of Nature
Man has invented an optical device called a lens. It is used in telescopes, microscopes, cameras and many other machines. By fitting several lenses together, Man can focus, enlarge and reduce what he sees.
Man has invented an optical device called a lens. It is used in telescopes, microscopes, cameras and many other machines. By fitting several lenses together, Man can focus, enlarge and reduce what he sees.
