Laser pointer experiment 5. Colors.
What is color? In fact, color is energy. Even though different #photons - light #particles - has different energies, wavelengths and frequencies, our eyes recognizing the different energies of photons. We also know from our experience that warming objects first starts to glow red, orange, until it becomes so hot, it radiates bluish light.
So color means energy... red, orange, yellow, green, blue, purple in this order has more and more energetic photons.
We can demonstrate simply this by a red, green and purple laser. I put some #fluorescein in the water and the #laser beams doing something completely different.
The red beam reflects from the water surface and only the red spot on the bottom shows that it went through the water also, but didn't interact with it. The green light is visible either in the air and the water. However the purple beam becomes bright green in the water.
The explanation is simple: red photons does not have enough energy to excite fluorescein #molecules. Green light excites some molecules, but not so much. Purple photons however #excite so many molecules that the beam disappeares and we can see only the green light of the excited molecules.
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