Hans Lippershey was the first to peek through his invention of the refractor telescope in 1608, followed closely by Galileo (although Galileo used his telescope for astronomy and Lippershey’s was used for military purposes). Their telescopes used both convex and concave lenses.
A few years later, Kepler swung into the field and added his own ideas: he used two convex lenses (just like the ones in a hand-held magnifier), and his design the one we still use today. We’re going to make a simple microscope and telescope using two lenses, the same way Kepler did. Only our lenses today are much better quality than the ones he had back then!
You can tell a convex from a concave lens by running your fingers gently over the surface – do you feel a “bump” in the middle of your hand magnifying lens? You can also gently lay the edge of a business card (which is very straight and softer than a ruler) on the lens to see how it doesn’t lay flat against the lens.
Your magnifier has a convex lens – meaning the glass (or plastic) is thicker in the center than around the edges. The image here shows how a convex lens can turn light to a new direction using refraction. You can read more about refraction here.
A microscope is very similar to the refractor telescope with one simple difference – where you place the focus point. Instead of bombarding you with words, let’s make a microscope right now so you can see for yourself how it all works together. Are you ready?
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