As we go about our everyday lives, we rarely stop to notice the physics that propel every action and reaction of the day’s routine. Physics is responsible for completing seemingly mundane tasks. From making our toast in the morning, to popping popcorn for a late-night snack, we rely on physical reactions to carry out these simple functions. When we stop to notice the physics and patterns in our world, a new appreciation of the wondrous beauty of our earth and civilization comes into focus.

The idea of popping kernels of corn into edible white fluff seems slightly bizarre when we stop to really think about it. But the physics that occurs during the process is equally fascinating. Microwavable popcorn does not allow us to witness the moment when all the activity takes place. However, if we pop the kernels the old-fashioned way, it enables us to take a peek at the physical reaction. The first step is heating a pan of oil. Once it is hot enough, the kernels are added, and a lid is placed on top. At first nothing seems to happen. The popping starts slowly and then soon accelerates to a flurry of activity. If we lift the lid, the white fluffy popcorn kernels can be seen bouncing about. 

The kernels themselves act like tiny pressure cookers. Each kernel contains the endosperm of a new plant. There is a certain amount of water in the kernel that can tolerate the hot oil up to a point of 360°F. Once that limit is reached, the endosperm of the kernel breaks free of the outer shell in the form of white fluff. As anyone who has made or eaten popcorn knows, there are always several kernels left unpopped. This disappointment occurs when the outer shell of the kernel is damaged or there is not enough water vapor inside, and the pressure cannot be created. 

The physics of activities such as popping popcorn can be explained by studying molecules and the way in which they interact with one another. The collisions among the molecules themselves as well as with the container they are in allows the pressure to be measured. The speed a molecule travels coupled with the number of times it collides with a container determines the outcome. Pressure is determined by the number and strength of the collisions. 

An individual molecule cannot have a temperature, but gas can. The molecules exchange energy each time a collision occurs within the cluster. They speed up or slow down depending on temperature. High heat speeds up the molecules and they begin colliding faster. The “ideal gas law” tells us that most gases behave the same way under similar conditions. This is the same law that creates the internal combustion in engines and the popping of popcorn.

We humans do not generally think about the constant pull of gravity as it moves us toward Earth. Our bodies were designed for a world with gravitational pulls. Even the act of walking uses the gravitational pull of our foot back to the ground. Each step we take is a display of gravity. The density of an object affects this pull. The less dense an object is, the less of a pull toward the Earth it feels. 

Gravity is a force that accelerates us. We can see how gravity alters our speed by using a high diving board as an example. When a diver first stands on the high dive platform, he or she is stationary. Once the diver jumps from the platform, his or her speed accelerates. Gravity is pulling the diver towards the water. The way the diver enters the water is crucial. Traveling at such a high speed upon entry requires straightening the body as much as possible to lessen the impact.   

Another aspect of gravity is “effective gravity.” It contributes to the feeling we get at the beginning or end of an elevator ride. When we feel a shift in our weight, it is due to the body being unable to tell the difference between the elevator accelerating and the gravitational pull moving the elevator. When the elevator ascends, we feel lighter as it reaches its acceleration speed. Upon the descent, we feel heavier as the elevator slows to a stop and gravity is pulling our bodies down. 

It is easy to see gravity at work when it comes to solid objects, but what about liquids? Archimedes was the Greek physicist who set out to find what causes objects to sink or float. This led him to the realization that there is a competitive force between the submerged object and the water that it displaces. This creates an upward push from the water, but gravity is still pulling the object downward. If the mass of the object is greater than the mass of the water being displaced, it will sink. But if the mass of the object is less, it will float. This is known as buoyancy force, and it is effectively the liquid world interacting with gravitational pull. 

While we try to appreciate the little things in life, we don’t always take the time to look at the extremely tiny things our world consists of. Small objects and occurrences allow us to appreciate life in a new way. For example, one rarely thinks about viscosity. Viscosity is the comparison of liquids by their molecular content. Water is not very viscous; therefore, it moves around easily. However, a sugary syrup is thick, and it takes more effort to break up its molecular clusters. 

An example of viscosity can be seen in the way milk is produced. Before homogenization, the cream (or fatty layer) of the milk would rise to the top. Fat molecules are less dense than water, so the viscosity of the water in the milk pushes the fatty cream molecules to the top. However, we no longer see these fatty molecules floating on the top due to the discovery of homogenization. Homogenization is a process discovered by milk manufacturers that squeezes the milk through very thin tubes which breaks up the fatty clusters. Therefore, the cream no longer rises to the top.

The principle that exists in homogenization is also at play when we sneeze. The size of the droplets produced from a sneeze will determine how far it is carried through the air. The particles that are within the droplets can contain certain airborne diseases. How far these droplets travel depends on the size of the droplet. Learning about this process has led to certain technological advancements. For example, the air ventilation systems in hospitals use technology that can remove these particles and help stop the spread of certain diseases. 

All of life’s events take place on timescales. A timescale refers to how long it takes for a process to be carried out. This could be anything from boiling water to a bird taking flight. And of course, timescales differ: The process of boiling water takes more time than the process of a bird getting airborne. And a snail’s movement? Its locomotion is on such a slow timescale because it has to pave its path forward with a mucus-like slime to get from A to B. This slime allows the snail to climb leaves and fences, and even allows the snail to glide upside down. Its mucus can act as a liquid or a solid, and the snail adjusts this depending on how fast and where it wants to go. When the slime sits still, its molecules form a chain, making it a solid. As the gel begins to move, the links of the chain break apart and it becomes a liquid. The snail may move slowly, and it’s all thanks to the slime it glides on.

The way pigeons (and certain other birds) walk provides another example of varying timescales. The pigeon steps forward, but its head stays in place. Then the head moves forward, and the body catches up on the next step. This movement allows the pigeon to see the world around it. The moment of pause enables the pigeon’s eye to send signals to the brain. Human eyesight works on a different timescale than a pigeon’s. We also see the world through our eyes, which then send the visual signal to our brain, but we can do this while in motion. Surprisingly, sending the visual signals to the brain happens only slightly faster in humans than it does in pigeons, but it does result in a timescale variation.

Human perception of time can vary as well. We live in the middle of timescales and, as Czerski explains, “It’s not just the difference between now and then, it’s the vertigo you get when you think about what ‘now’ actually is.” Everything in the physical world is searching for balance. The world may never find absolute equilibrium, as that would mean the end of all forces. But we can find balance in certain aspects of life, as well as certain technological advancements that allow us to alter these forces to find equilibrium. The Hoover Dam is a great example of a man made tool that enables us to control the water flow and, subsequently, the energy it creates.

When we look out at the ocean, the movement of the waves is easy to distinguish. The small ridges and ripples in the water soon crescendo to the foamy crests that crash ashore. The way a wave travels through the ocean mimics the movement of other waves we encounter daily. Sound waves, air waves, and radio waves may not be obvious to the eye the way the ocean wave is, but they are all vitally important to our modern civilization. 

Every type of wave has a wavelength, a frequency, and a speed. Wavelength is the measurement of the distance between the peaks of the wave. The frequency of a wave is the number of times it goes through a cycle from peak to valley and back. The speed of a wave depends on the wavelength. Although sound waves and light waves cannot be seen, they contain these same three features.

Reflection is the act of bouncing waves back from a source of light. All waves can be reflected. The “color” silver is the perfect example of this: It is not really a color, but a way in which light is bouncing back into view. Certain types of fish are silver, and this acts as a defense against predators. The light of the sun reflects off the fish and camouflages it in the water. 

Just as waves can be reflected, they can also be refracted. Refraction is the act of changing the direction of a wave by changing its speed at different points of the wave. For example, anything light passes through slows it down. The depths of the ocean are dark because light can only pass through the water surface and then it slows down to the point of darkness. The “speed of light” occurs only when it travels through nothingness. Light is slowed down 75 percent by water and 66 percent by glass. A diamond only slows light down by 41 percent which is what makes diamonds so sparkly. Refraction also leads to the science behind lenses. Microscopes, telescopes, and cameras all use refraction to transmit images to the human eye.

Magnetism is a fascinating feature of certain metals and alloys such as nickel and steel. The magnetic field is what surrounds an object and can push or pull other magnetic objects around it. All magnets have a north and south pole. The north pole of one magnet is attracted to the south pole of another object. However, two north or two south poles repel each other. The North and South Poles of Earth work exactly in this way. The movement of the iron in the Earth’s core creates a magnetosphere that keeps our planet spinning on its axis. Due to fluctuations in the magnetosphere, the North and South poles shift ever so slightly over time, even completely flipping every 300,000 years or so. But thankfully, nature seems to adjust to these miniscule shifts. A compass can adapt to the shift and always find the magnetic north, even if it is not the mapped location of the North Pole.

Magnets have a huge impact on our daily lives as they are an integral part of how we harness our electricity. Electromagnetism is the physical interaction between magnetic fields and electric charges. Electrical charges act the same way a magnet would in that they attract different charges and repel like charges. Science and technology use this knowledge to provide us with electricity.

Static electricity is something that occurs when charged particles are transferred from one body to another. We have all experienced the unwelcome “shock” of touching something that is oppositely charged from us. It usually happens in winter when the surrounding air is dry. Humid air allows the electrons to escape, but when the air is dry, the electrons have nothing to absorb them. The result is a slightly uncomfortable static “shock.”

A bumblebee also has the ability to generate electricity  to attract nectar.. The rapid fluttering of a bee’s wings generates an electrical charge much like static electricity. This makes the bee attractive to the pollen particles in a flower. The particles begin to hop onto the bee before it even lands on the flower due to the pull of the bee’s positively charged electrons. When the bee flies to the next flower for more nectar, the pollen from the previous flower travels with it, furthering the pollination process. Bees do not need to rely on their static electricity to pollinate, but it does make it easier for them.

Our body is what carries us through life and around this beautiful planet, and it has many functions that should be appreciated. But our bodies would not be able to carry out these functions if it were not for the elements of the planet we inhabit. Oxygen enables us to breathe, water keeps our bodies hydrated, and even our sense of smell can be attributed to the molecular makeup of aromatic cells. These are just a few of the connections between our bodies and our planet.

Gravity enables us to feel the pull to Earth, however, it’s just the right amount of pull so that we may continue to move freely.  The body then provides the balancing power of inner ear fluid. The way the human body works together with the gravitational pull of Earth to keep us upright and balanced, is wonderous thing.

The Earth is made from ice, atmosphere, ocean, rocks, and life. These components participate in a constant and beautiful dance that makes our planet inhabitable. Looking down at Earth from space allows us to see these components: The green and brown of land, the blue atmosphere of the sky, and the white clouds of our weather patterns. The Earth garners the energy from the sun to keep things in constant motion. The tides of the ocean rely on the moon to keep that constant movement replenishing the shoreline. The sand is swept in and out during the different tides, but it always remains to provide a buffer between land and sea.

Civilization has provided humans with everything from farming to providing electricity. Society relies on energy and innovation to keep improving from one generation to the next. This process of ongoing improvement stretches back to our discovery of fire. Once fire was discovered, humans were able to invent  the candle and  eventually electricity. Earth has a way of naturally storing the Sun’s energy in fossil fuels. These fossil fuels enabled us to provide energy for civilization, however, their use has now resulted in a warmer planet. 

The connections and patterns between our bodies, the Earth, and civilization can be seen all around us. Sometimes we just need to stop and appreciate how these patterns make our world not only inhabitable, but beautiful as well. Helen Czerski sees the beauty of these connections as she looks into the swirling liquid of her afternoon tea: “Reflected from the liquid surface is a similarly bright, beautiful, and fascinating pattern, an image of the sky above my head. Right there, in my teacup, I can see the storm.”

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