Updated: Oct 4
What is color? And how do we see it? From an artistic perspective, it is described by hue, value, and Intensity. But defining it scientifically is different.
When light hits an object, it reflects light. Which is then absorbed by the object, and the object reflects wavelengths of light. Different objects reflect different colors. For instance, a strawberry reflects a red light. Black objects appear black because they absorb all wavelengths of light. Objects that reflect all wavelengths appear white.
Did you know scientists believe the average human can recognize approximately a million colors!?! That's quite amazing, but how are we able to see color? Let's start by looking at a diagram of the eye.
Light travels into our eyes through the cornea and enters the pupils. The pupil is surrounded by the iris(the color of the eye). The iris controls how much light enters by contracting in bright sunlight or expanding in dim light. The lens works with the cornea, a transparent concave structure that helps bend light by using the ciliary muscles attached to the lens to change shapes to focus at varying distances. The focus light is sent to Our retina, which is home to cells called cones and rods. These cones and rods allow us to see color once the retina has processed all the information; it is sent to the brain's visual cortex via the optic nerve, where the magic happens and the image takes shape. How many colors are visible depends on how many cones and rods are in an individual's eyes. I am no ophthalmologist or scientist, so check out this awesome video from the experts at The American Museum of Natural History for even more insight.
Exploring How We See Experiments
1. Your Pupils
Look closely at the eye in the video. Did you notice any changes when we turned the light on? The pupil contracted to allow less light into the retina. In darker conditions, the pupils expand, allowing more light to enter for better visibility.
This Mel Chemistry Kit was a perfect extended activity for this lesson. It helped us "explore the intricacies of color subtraction." Head to Mel to learn more about these experiments or purchase a kit. Or, if you have colorful cellophane paper and a flashlight, you could recreate the color-mixing experiment yourself.
3. Light and Glass
Because light plays a significant role in seeing color, let's explore what happens when light travels through glass and water. Light reacts differently depending on the medium. Let's grab a glass and a flashlight or place it in the sun. Since the class is transparent, it doesn't absorb light. Observe how the light is reflected. Can you see the light being bounced around near the glass? The light is reflected and refracted through and off the glass. When light travels through the water, it is refracted, meaning that it slows down and bends to travel in many different directions. Looking closely, you may see the rainbow bouncing back at you because of the light bouncing off the glass.