Ordinary Things Scientists Don’t Actually Understand

Yawning is one of those physical actions it seems impossible to escape. In addition, anyone who has been in the presence of someone else who is yawning can attest to a simple fact: it’s contagious. Given how common yawning is and how quickly it seems to spread, it is all the more remarkable to discover how little science actually knows about it.

Prevailing wisdom suggests the process is the body’s way of getting more oxygen-rich blood to the brain, since it seems possible humans take fewer deep breaths when they are tired. However, the actual neurology behind the need for this particular process is still somewhat lacking. Many other animals yawn as well, however. The contagiousness of yawning may stem from social mirroring, which is the process by which animals mimic the behavior of others, particularly those actions that might seem to be beneficial.

While the reasons for laughter can vary widely from culture to culture, this does seem to be one of those things that binds humans together. Since it’s so common, one might think science would have found some unifying theory to explain humor but, instead, the opposite is true. Even now, scientists struggle to find a way of explaining in a systematic fashion just what humor is and how it works.

New research has suggested humor stems from the violation of a social or physical norm, yet not to such an extent it would trigger a fear response. Some evolutionary biologists have also suggested laughter might have played a role in fostering social bonds and cohesion and, since this would increase the odds of group survival, it meant such a behavior would be reproduced in the next generation. Still others have proposed humor might stem from the juxtaposition of expectations and reality.

Anyone who has undergone any kind of surgery has had an encounter with anesthesia. It is, after all, the phenomenon that has allowed such invasions of the body to be far less painful than they were in the past. However, despite how common anesthesia is in medical practice – used throughout the world many thousands of times each and every day – there has yet to be a scientific consensus on why it works.

For some time, it was believed the process affected the fatty parts of the brain, interrupting neural activity there. It’s now believed certain receptors in the brain attach themselves to the anesthetic, which leads to a loss of sensation and consciousness. Moreover, scientists increasingly speculate there may be a variety of processes at work, rather than one simple idea that would explain all the others.

Sleeping is, of course, an act with which everyone is familiar, given its necessity to human functioning. However, despite being a universal experience, scientists have yet to fully figure out just why humans – or other mammals – need it. After all, sleep poses many evolutionary challenges, largely because it renders humans and other mammals susceptible to predation.

Experiments that have attempted to genetically remove the need out of subjects have never succeeded. Scientists also remain unclear as to the mechanisms the body uses to put itself to sleep, as well as how each individual determines how much sleep the body requires (the usual balance is not too much and not too little).

However, though certainty eludes them, scientists do have some working theories about why humans need to sleep every day. Research suggests the brain conducts important maintenance during sleep, including forging connections between different parts of this vital organ. What’s more, the brain has also been shown to clean out waste chemicals during the time when people are sleeping.

Tylenol is one of those over-the-counter drugs that has become nearly ubiquitous. After all, one can walk into almost any drugstore or gas station and find it for sale. It’s easy to see why this would be the case, as it is often effective at dulling various sorts of ordinary pain. However, what is surprising is how little scientists know for sure about how it (and its generic form, acetaminophen) functions and why it is so effective at mitigating pain.

In fact, the physician’ note that accompanies the bottle is clear about the fact: It’s simply not known either where the medicine works or the process it uses to do so. Research suggests its efficacy may stem from any of a variety of sources: Because it blocks an enzyme involved with the sensation of pain; because it engages with the endocannabinoid system (which is also involved in feeling pain); or by adjusting the signals sent by serotonin. It is also possible, and even likely, it is a combination of all three.

Cats are known for many things, but one of their most well-known characteristics is the purr. If one has ever had a cat – or even just encountered one that belonged to someone else – then one is likely to have heard this sound, the cute rumble which seems, according to the prevailing wisdom, to signify the little ball of fur’s contentment. However, cats are also known to purr for a number of other reasons, and some even do it when they are frightened. What’s more, not all felines can do it, with some of the big cats such as lions and tigers unable to do so.

Though their motivations remain fuzzy, most scientists have come to believe cats engage in this behavior as a soothing mechanism. What’s more, there is also evidence they may do it in order to encourage bone growth, since the frequency at which they purr encourages the regrowth of tissue.

Crying is, of course, one of the experiences almost all people have had at one time or another. On the one hand, the process has a physiological benefit, as it helps to wash away debris from the eyes. However, its linkage to emotion seems to be unique to humans, and there isn’t yet a consensus on why humans have developed this particular behavior, as emotional crying has no specific linkage to a physical benefit.

Though there seem to be some chemical differences in emotional tears (as opposed to, say, those shed while peeling an onion), there isn’t yet a consensus as to what physical good crying does.

As with many other physical processes, however, it seems this one developed as a social mechanism. For example, it could have developed as a means of encouraging others to develop empathy, or to demonstrate submissiveness (thus averting more violence). And, because tears are so evident on the face, they remain a key way for humans to communicate their feelings to others.

For many people, going ice-skating is a key part of winter life. It is another of those everyday phenomena, however, that many people take for granted and which lacks a concrete explanation from science. Previously, it was believed the pressure of the skate raised the temperature of the ice enough so it would start to melt, and the resultant skin of water enabled the skater to glide across the ice. Unfortunately, this hypothesis doesn’t hold up.

In fact, it would take a significantly larger amount of pressure in order to raise the melting temperature of ice, far more than any skater is likely to bring to bear.

While it’s still unclear about the mechanism that allows ice skating to take place, there are some working theories. One proposes the water molecules at the surface may not be bound as tightly, while others propose there are flaws in the structure of ice that allows for it to enter the liquid state.

One of the most common science classroom experiments involves a balloon, and most people are familiar with the feeling of running it across one’s hair and generating a static charge. It’s such a common feature most people don’t even think about what causes it. Scientists, however, have done so, but they remain unclear about the mechanisms involved or why it happens the way it does.

At one point, it was believed the static charge occurred because of the interaction of the two different materials, each of which carried different numbers of electrons. However, recent experiments have shown this particular explanation doesn’t hold water, as it doesn’t explain why static charges can also build up between objects of the same material. Even the prevailing explanation for this, which states the difference in size accounts for the charge, also doesn’t work.

The prevailing theory among researchers suggests there may be other molecules that are being transferred in the contact.

There are few things more pleasurable than dipping one’s bare feet into the sand at the beach. The soft texture of it seems to be innately calming. However, for scientists, the softness of sand is also perplexing, precisely because there is so much about this particular tactile quality that eludes understanding.

For example, most people notice how sand on the surface of the beach feels softer than the layers underneath, because the latter have been compacted. Nevertheless, scientists have spent a great deal of time studying this very common material, and some rules do seem to apply. For example, the smaller the grain, the more likely it is the sand will feel soft, because they are able to move more easily. On the other hand, if they are too small, moisture will often make them stick, negating the soft feeling and replacing it with a clumpiness.

Bicycles, like so many other means of transportation, are such a regular feature of everyday life it is easy to take them for granted. After all, they are a staple feature of modern life, and they are increasingly used by those who wish to avoid the hassle and headache – and environmental impact – of cars. Those who use them might be surprised to learn, however, just how little science knows about the very mechanism that is key to their use: how they stay upright when moving.

At this point, the only thing most scientists know with any certainty is this: the pedal turns the gear which turns the wheel. The most enduring question is: Why is a bike stable enough that if one releases it while it is in motion, it will continue until it slows down and falls on its side?

One theory suggests it’s the spinning wheel that gives the bike its stability, but this doesn’t explain why the bike remains balanced. The other proposes the wheel is like the caster on a shopping cart, except it too was proven to be largely wrong. Much research is still needed to explain this phenomenon, and an entire center in the Netherlands is devoted to exactly this inquiry.

Getting the hiccups can be a truly unpleasant experience, particularly if they do not go away quickly. Most people have experienced this unpleasant sensation at some point in their lives and, while they often go away on their own, they can last for a surprisingly long time. And, despite how common they are, scientists remain as in the dark about what causes them and what they do (to say nothing of how to cure them), as they have always been.

Of course, science has come up with a number of theories as to why humans hiccup. Some suggest it’s a holdover from an earlier stage of evolution, while others think it might have to do with the need for baby animals to get rid of excess gas. As of yet, there have been surprisingly few systematic studies on the mechanics and causes of hiccups, let alone how to get rid of them.