Misconceptions

Most of the concepts in science are clear and easy to associate with our daily life, but there are concepts and theories that are often misinterpreted.

Fundamental theories such as those related to classical mechanics are clearly understood; cases such as optics, thermodynamics, speed and acceleration, momentum, energy and others are easily assimilated, as they relate to our daily life.

Other cases, such as those related to quantum mechanics are known, but might as well not be seen as related to our daily activities; even when in fact they are, as these are involved in almost everything we do on a daily basis; a simple example is that of digital technology, used in all types of electronic devices, which work based on quantum effects, nothing closer than this, since nowadays virtually we all live with an electronic device within reach, say cell phone, computer, TV, etc.

But even with the ease with which information can be obtained, there are still some cases in which certain ideas are incorrectly explained or is just that information about new theories is not easy to assimilate and therefore is incorrectly interpreted. Here are some examples.

 

Fundamental particles.

Surely in your school years you learned that everything that surrounds us, and even ourselves, are made of molecules, which in turn are formed of atoms.

Finally, we learned that atoms are made of three fundamental particles, the electron, the proton and the neutron. With the consideration that everything in the world is constituted of these three particles; a nucleus composed of protons and neutrons with a series of electrons orbiting them.

This model works to give a clear image of the atomic model, something like the solar system, easy to understand, but not entirely correct.

Without going into further detail, the reason why this model is not precise is because, unlike the electron, both the proton and the neutron are not fundamental particles, since both are constituted by another type of particles, the quarks. As discussed in The standard model, the proton and neutron are each formed by three quarks; the most interesting thing about this is that, to have the proton with positive charge and the neutron with neutral charge, the quarks have a partial or fractional charge. As in the case of the Up-quark with load of +2/3 and the Down-quark with load of -1/3; considering this, the proton is formed of two Up-quarks and a one Down-quark, having a total charge of +1; and the neutron has two Down-quark and an Up-quark, with the total resulting charge of zero.

Proton and Neutron

Proton and Neutron (nuclear-power.net)

You could go deeper into the case of electrons, because these are not small marbles flying around the atomic nucleus as we have learned; in fact, electrons behave like fields or waves of potential, which obey quantum laws, and can behave like waves or particles. If it were not for this property, the electrons would inevitably collide with the positively charged atomic nucleus (since opposite charges attract each other), and there would be no way for the atoms to form.

 

Light travels at a constant speed.

Another example of a concept that is frequently wrongly explained is to consider that light “travels”, and that it does so at a constant speed.

It is common to hear the concept of the speed of light, this value is used as a reference to measure distances; For example, it has been defined that the closest star to us on earth is 4.24 light-years from us, that is, that the light that we perceive from this star was produced 4.42 years ago.

But, in essence, it is not the light that travels, what we understand as light, it is really a disturbance; which combined have an effect on an electric field and a magnetic field; the disturbance of the electric field causes in turn a disturbance of the corresponding magnetic field, which in turn disturbs again the electric field, and so this sequence continues. This mechanism allows the light to propagate, and makes unnecessary for the light to have a medium to propagate (as in the case of sound that needs a medium such as air or water, being a mechanical wave). The light can continue with its propagation until it hits something, for example the sensor of a telescope, or the body of a person having a “sunbathing”.

Electromagnetic wave

Electromagnetic wave (wikipedia.org)

And why do we say that light spreads? Well, this is because what is moving is this disturbance, but it is not that something tangible moves from a point “A” to a point “B”, it is only that the disturbance is transferred from one point to another, but in reality, nothing moves.

Also, the light does not move at a constant speed, its speed is dependent on the medium in which it moves, it is said that the speed of light is constant in the vacuum, but outside a vacuum, in a different medium, this speed is diminished.

The speed of light in the vacuum is almost 186,000 miles per second, or exactly 186,282 miles per second. However, in the air, this speed is 186,226.5 Miles/s, almost 60 miles/s less than in a vacuum, and depending on its density, this speed decreases even more.

– On the water 139,746.7 miles/s
– On the Quartz, 127,590.6 miles/s
– In the Zirconia, 97,022.1 miles/s
– In the diamond, 77,071.7 miles/s

As you can see, in the case of the diamond, the speed of light is less than half that of that on the vacuum, this has to do with the refractive index of the medium, the light always maintains a constant speed, unless it is disturbed (refracted, reflected, diffracted, etc.), and that’s what happen in such materials; Another interesting effect is that, with this decrease in speed, there is also a decrease in its wavelength, but its frequency remains constant.

Light in a medium different from vacuum

Light in a medium different from vacuum (speed_micro.magnet.fsu.edu)

 

The gravity is strong.

We feel the force of gravity on a daily basis, and we know its consequences if we do not take it into account, when falling or when trying to load something that very heavy (or massive). Maybe this is why we consider that the force of gravity is huge; but in reality, the force of gravity is the weakest of the four forces in nature; for example, compared to the electromagnetic force, the force of gravity is 40 orders of magnitude lower. The gravity is so weak that we can counteract it easily, at least momentarily; when jumping a rope, the force we generate is greater than that of gravity; even the force from a magnetic field can counteract gravity, as in the case of electromagnetic cranes, which can lift several tons of metal at a time.

Electromagnetic crane

Electromagnetic crane (sinkokocrane.com)

Quantum effects only occur at very small scales.

True, quantum mechanics has many effects that are not easy to understand, such as the duality particles have to behave as a wave or as a particle, depending on whether they are observed or not. The case also of the tunnel effect, where a particle can cross a physical barrier as if it did not exist, simply disappearing on one side and reappearing on the other. Or the ability of particles to maintain two states at the same time, which implies that a particle can be in two places at the same time, an effect that is called superposition.

All these quantum effects are known and can be calculated and are key to having many of the objects and services that we enjoy today, such as the aforementioned microelectronics; Another example is the case of bar code systems, which are also based on quantum effects. But can these effects only occur at the subatomic level?

Well is at that level where they constantly manifest, quantum effects are closely linked to probability, and the more particles involved, the less likely it is that these effects will manifest themselves.

Even so, quantum effects have been detected in atoms, and other larger objects such as fullerene molecules that have a Bucky ball shape and are composed of 60 carbon atoms. And, even in objects that can be observed with the naked eye, as in the case of an Aluminum Nitrate resonator, where superposition was detected in an experiment carried out in 2010 by the University of California at Santa Barbara.

Buckminster Fullereno

Buckminster Fullereno (wikipedia.org)

But, what about larger objects? Let’s say a person. Can a person experience a quantum effect and for example, have superposition and be in two places at the same time? Well, in essence, it is possible, but as we discussed, this has to do with probabilities, and the human body is composed of a huge number of particles that form different atoms and molecules. In itself it is estimated that an average human of 70Kg can have around 7×1027 atoms, or seven octillions of atoms.

If we consider that for a quantum effect to occur at the scale of a human, it is necessary that this effect occurs in each of the subatomic particles of all these atoms, simultaneously; this probability, even when is not zero, it is extremely small. If we considered, that a possible quantum state would happen in a person every second, this would imply that we could witness the superposition of a complete person (or be able to see the same person in two different places), once in approximately nine billion times the amount of time elapsed since the beginning of the universe (from the big-bang), until now, so, yes, it is possible that this happens, but it is extremely, extremely unlikely.

This type of incorrect ideas and misunderstandings can be due to many factors, one of them may be having so much information, with different interpretations of it. But even with these details and surprises, what is more interesting in science is that it is always a series of discoveries, as soon as we understand an aspect of the nature that surrounds us, new mysteries are discovered, this is a cycle that, till now, it seems to have no end.

Regards, Alex
ScienceKindle!

 

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