To understand spectra you need a little primer on light first
It is helpful to think of light and sound together
They are both wave phenomena
Sound is a mechanical wave
Light is a electromagnetic wave
You can think of color as pitch and brightness as loudness
Red would be on the low side of the scale (bass) and violet would be on the high side (treble)
The range of colors is called the visible spectrum
What would be lower than low?
What would be higher than high?
A Low Note
A High Note
Here’s what all possible pitches together would sound like:
What would it look like?
All possible colors added together with the same brightness make white
I know, you’re thinking “but if I mix all colors of paint together, it’s black.”
True, but paint doesn’t make light, it absorbs light. If paint absorbs all colors, what would you have?
Showed with a prism* that white light is a continuous band made of all colors
*How does a prism do this? I’ll explain the Physics after class if you wish.
A contemporary and adversary of Newton
Declared the prism to be the "usefullest Instrument" for gaining insight into the fleeting array of colors generated when sunlight passes through it.”
100 years after Boyle, Herschel viewed starlight through a prism
Saw differences in the width and intensity of the colors of the spectrum
Also detected “invisible rays”
Used a thermometer on each color and found “temperature” below red
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Long before that, though, scientists were interested in improving on the design
One goal was to increase angular dispersion