Transcript:
When you go outside of your home, you see yellow daffodils, white daisies, red roses, blue irises blooming around you. As you peer across your lush green lawn into the horizon, you see blue sky fading into pink, orange, and red hues as the sun sets. Colors are everywhere! Have you ever wondered where the colors come from? Well, the colors you see are not actually colors; they are electromagnetic waves!
The visible light you see is a form of energy, like heat and sound. Light, or electromagnetic energy, can travel as waves or particles. Sometimes behaving like waves, sometimes like particles, but never like both at the same time. Let’s use a famous optical illusion drawing (young lady and old woman) as an analogy to understand light’s behaviors. In the illusion, you can see either a young lady or an old woman but never at the same time. Young lady or old woman are not two halves contained in one drawing. Either image encompasses by itself the entire drawing and neither of which reveals the true nature of the drawing. Depending on how you perceive the drawing, you observe two images out of this oneness. We can think of light having an “oneness” with two “faces,” particles or waves. Depending on how we or other objects interact with it, the light will either behave as particles or waves.
There are many different types of electromagnetic waves (i.e. infrared, radio, microwave, x-ray). They can be determined by wavelength, or distance between each successive wave. The electromagnetic waves lie on a spectrum with longer wavelength at one end and shorter wavelength on the other end. Visible light takes up only a very small part of this spectrum and it is the only part of the spectrum we can see. We cannot see energies with longer wavelengths than visible light like infrared waves or shorter wavelengths like x-rays. Within the visible spectrum, red light has the longest wavelength, green light has the medium wavelength, and violet light has the shortest wavelength.
These wavelengths are not colors just yet! Human eyes have cones – a sensory structure that respond to visible light. Cones can only recognize the wavelengths of light in the visible spectrum. There are three types of cones that detect different wavelengths: short, medium and long. Together, they allow the brain to perceive the signals from the wavelengths into different colors! If we see a red rose, it means the flower has absorbed all of the wavelengths and reflected the red wavelength back to our eyes. Our eyes interpret this wavelength and see red as a result. If we see a white cloud, it means the cloud has reflected all of the wavelengths and we see all of the colors together in the form of white. If we see a black car, it means the car has absorbed all of the wavelengths and we see no color (i.e. black).
When you take a moment to enjoy the brilliant display of colors in our world, remember that these colors are actually light, or electromagnetic, energy traveling towards our eyes and interpreting by our brain as colors!
