In our series of senses we’ve already explored the science behind taste and how we smell, so it seems only right that we take a look at the sense that seems to be the most advanced of them all. Furthermore, supplying biology equipment, including models of eyeballs, means that we find the process that enables us to see completely fascinating!
How Our Eyes Have Evolved
Scientists believe that our eyesight has evolved over millions of years. From what was once nothing more than a sensor to distinguish light from dark, we can now see different wavelengths of light.
Humans can see the world through three different wavelengths – red, green and blue. However, most other mammals see the world in yellow and blue, which is thought to be because two of the four cone types were lost during mammalian evolution.
Some other animals, such as certain species of fish, birds and reptiles have four-colour vision. This means that they are also able to see ultraviolet or infrared light.
The Route an Image Takes
In order for us to make sense of the different wavelengths and colours that we see, the light has to take a specific route through our eyes for it to be interpreted as our surroundings.
The cornea is the eye’s outermost lens, protecting the eye and focusing the entry of light. Light first passes through the cornea and then into the pupil. In order to limit the amount of light that enters the eye, the circular and radial muscles of the iris contract and relax to alter the size of the pupil.
The light passes through to receptors at the back of the eye that then transmit the data to our brain.
How We Can See in 3D
Technically, our eyes are only able to produce 2D images. However, because of the processing of these images, we are able to interpret depth. Furthermore, the distance between our eyes means that we are able to see the world from slightly different angles. Our brain compares these two pictures to create the illusion of depth.
We hope that you find the science behind our sense of sight as fascinating as we do!
If you’d like to purchase science equipment to help you teach your pupils all about eyesight, please don’t hesitate to contact us by calling 01366 385 777.