Sir Isaac Newton of Cambridge University in England, first uncovered the secrets of how light is divided up. We think of ordinary light as being ‘white’, but really light is a mixture of red, orange, yellow, green, blue and violet. When sunlight strikes the bevelled edge of a mirror, or the edge of a glass prism, or the surface of a soap bubble, we can see the different hues in the light. What actually happens is that the white light is broken up into the different wave lengths that are seen by our eyes. These wave lengths form a band of parallel stripes, each hue grading into the one next to it. This band is called a ‘spectrum’. In a spectrum the red line is always at one end and the blue violet lines at the other.
Fact File Sir Isaac Newton used his discoveries about light to build a new kind of telescope. It used a reflecting mirror instead of glass lenses to magnify images. |
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