By: Annie Sragner, Associate Arts & Life Editor
The physical world around us may seem simple or mundane at times, but every aspect of our environment is governed by forces and numbers.
For example, as a student sits in class listening to a lecture, the earth is pulling that student in the chair down with force equal to 9.8 meters per second squared. This vital value of gravity constantly tethers our bodies to the surface of Earth, and any less force would send us flying around in the air.
This is why people are tallest when we first wake up in the morning. Gravity slowly pulls our bones toward the ground throughout the day.
Without resistance for our bodies to overcome, our muscles atrophy, or deplete, because the enzymes and proteins that constantly keep us moving start to breakdown. When a person is in a coma or on bed rest for as short as a week, leg muscle mass can decrease up to 10 percent.
Every sound and sight we perceive is also a consequence of physical forces. Invisible to the naked eye, there are countless wavelengths bouncing off every surface around us.
Our visible light spectrum is just a tiny fraction of all the wavelengths out there. In our eyes, we have receptors called rods that detect light and motion, and cones that detect colors.
Human cones can only see from about 400 nanometers, which is violet, to 700 nanometers, which is red.
Other species, like the mantis shrimp, have a wider vision spectrum and can see from 300-720 nanometers, which is from ultraviolet to infrared, respectively. If we could see like a mantis shrimp, we could see the signals from our remote controls and some waves from the sun.
Aquatic creatures see the world much differently than land-dwellers do. Light travels with a refractive index of one on land and 1.3 underwater, which makes water harder to see through.
This is why fish typically have thicker eye lenses than humans in order to see in this denser environment.
This difference causes light rays to bend about 13 degrees as they go from air into water. Fishermen take advantage of this bending when sizing up a fish they want to catch. Fishermen will often aim slightly behind the fish’s apparent location because human eyes do not account for this bending.
The physical world around is much more complex and bustling than we can realize at a glance. This finely-tuned orchestra of forces creates the sense that we make out of our environment.
Consider other ways in which physics makes everyday life possible for you.