#physics #scale #laws #universe #scientifictheory
Have you ever wondered why physics seems to work differently depending on the scale at which you’re observing it? 🤔 It’s a fascinating aspect of the natural world that many people find perplexing, but fear not – we’re here to shed some light on this intriguing topic!
## Understanding Scale in Physics
When we talk about the scale in physics, we’re essentially referring to the size or magnitude at which we’re observing a particular phenomenon. Whether we’re examining the behavior of particles at the subatomic level or the dynamics of celestial bodies in the vast expanse of space, the laws of physics seem to manifest in different ways at different scales.
### The Macroscopic World
In the realm of everyday human experience, classical physics – which encompasses Newton’s laws of motion and the principles of thermodynamics, for example – appears to reign supreme. These laws provide us with reliable predictions about the behavior of objects and systems at the macroscopic level, allowing us to build bridges, design cars, and send rockets into space with a high degree of confidence in the outcomes.
### The Microscopic World
However, when we venture into the realm of the incredibly small – the world of subatomic particles and quantum mechanics – the rules of the game seem to change entirely. Instead of the deterministic, cause-and-effect framework of classical physics, the behavior of particles at this scale is characterized by probabilities, uncertainties, and surreal phenomena such as entanglement and superposition.
## Theories of Physics on Different Scales
So, why does this dichotomy in the behavior of physical systems exist across different scales? Let’s explore some of the key theories and concepts that help to explain this intriguing phenomenon.
### Quantum Mechanics
At the microscopic level, the principles of quantum mechanics govern the behavior of particles such as electrons, photons, and quarks. Quantum mechanics introduces us to the concept of wave-particle duality, where particles exhibit both wave-like and particle-like behavior, and the uncertainty principle, which places fundamental limits on our ability to simultaneously know certain pairs of properties of a particle.
### General Relativity
On the other end of the scale spectrum, we have the theory of general relativity, which describes the behavior of massive objects and the curvature of spacetime. General relativity provides an elegant framework for understanding the large-scale structure of the universe, including the bending of light around massive objects and the dynamics of black holes.
### Unified Theories
In the quest for a unified theory of physics, scientists are working to reconcile the principles of quantum mechanics and general relativity – two theories that currently seem to operate in fundamentally different ways. The pursuit of such a unified theory, often referred to as the “theory of everything,” holds the promise of providing a single framework that can accurately describe the behavior of physical systems across all scales.
## Emergent Phenomena and Complexity
In addition to the theories that underpin our understanding of physics at different scales, it’s important to consider the concept of emergent phenomena – those that arise as a result of the interactions and collective behavior of simpler components. These emergent phenomena can give rise to complex systems that exhibit behaviors and properties not easily predicted from the individual components alone.
### Examples of Emergent Phenomena
– The behavior of a flock of birds or a school of fish, which can exhibit coordinated movement patterns without any central control.
– The formation of intricate snowflake patterns from the simple interactions between water molecules.
– The emergence of consciousness from the interactions of billions of neurons in the human brain.
## Implications for Our Understanding of the Universe
The realization that the laws of physics can operate differently at different scales has profound implications for our understanding of the universe and our place within it. It challenges us to question our assumptions about the nature of reality and pushes us to explore new frontiers of scientific understanding.
### Practical Applications
– Understanding the behavior of materials at the nanoscale is essential for developing advanced technologies such as quantum computers and nanoscale electronics.
– Exploring the dynamics of galaxies and the structure of the universe at cosmological scales can provide insights into the origins and ultimate fate of the cosmos.
### Philosophical Reflections
– The duality of deterministic classical physics and probabilistic quantum mechanics raises profound philosophical questions about the nature of free will, causality, and the fundamental fabric of reality.
– The emergence of complex phenomena from simple building blocks challenges our reductionist view of the universe and invites us to consider the nature of emergence and complexity.
## In Conclusion
In conclusion, the fact that physics works differently depending on the scale at which we’re observing it is a testament to the richness and complexity of the natural world. From the bizarre and counterintuitive behaviors of quantum particles to the majestic dance of celestial bodies in the cosmos, the study of physics on different scales offers us endless opportunities to marvel at the wonders of the universe.
Whether we’re peering into the subatomic realm with particle accelerators or gazing out into the depths of space with powerful telescopes, the pursuit of understanding the physics of different scales continues to inspire and challenge us. As we strive to unify our theories and deepen our understanding, the mysteries of the universe remain an endless source of fascination and discovery.
Physics works differently at different scales due to the principles of quantum mechanics at small scales (atoms and subatomic particles) and general relativity at large scales (cosmological and massive objects). These theories describe phenomena that deviate from classical physics, leading to distinct behaviors in the microscopic and macroscopic worlds.
Let me choose an example you are familiar with. On a one-meter, surface tension does not matter very much. Yet at the scale of 1mm, surface tension (with water) is dominant. So, bugs can walk on water, and you can get beautiful drops of water on pine needles.
The laws of physics aren’t different, but when calculating the force on an insect foot on a lake, surface tension is important compared to mg. Less so with a human foot.
Physics itself does *not* work differently at different scales. Objects of all sizes from ants to galaxies are made of the same tiny particles like molecules, atoms, electrons and quarks. they follow the same rules, and interact through the same waves like microwaves, visible light, and X-rays.
However physics *appears* to work differently when we focus on a certain scale and try to tell a simple story. For example a basketball bouncing on the floor, or a chemical reaction, or a rocket taking off, or a star exploding into a supernova. For each of these, going back to the behavior of elementary particles to try and piece the whole story together would be way too complicated. But at each scale, we’ve often been able to come up with a few simpler rules that do the job. We don’t care about what happens to atoms in the basketball or molecules in a glass of water, so we can make the story much simpler.
It’s a bit like a historian talking about an army marched against another army, instead of talking about how a particular grain of sand ended up in the pocket of soldier #13546834. At some point we decide that the details don’t matter.
Physics is trying to translate what we observe into a mathematical language.
The goal is to keep the math as simple as possible. To do that, we limit the scale. When you throw a baseball in the air, it comes down. Simple math. If you throw a feather in the air, it comes down and there’s air resistance. Slightly more complex math. If you launch a rocket into orbit… even more complex math.
Overall, we’re trying to keep the math as simple as possible while still getting meaningful answers for whatever system we’re observing at that time.
At present, we’re still working out “Grand Unification” that will bring all the different scales together.
I’d argue it doesn’t really. It’s the same on all scales.
It’s just at larger scales we can make simpler approximations and still get accurate results. So why go through all the work?
It’s like how one person clapping creates a rythmic periodic sound. But as you add more and more it turns into a steady roar. At some point you can just treat it as one single sound rather than a combination of lots of smaller ones.
The actual mechanics of the origin of the sound are the same. But you don’t have to be that detailed in modeling the sound anymore. You can say it’s a single source with a specific intensity and disperses by the inverse square law.
Physics doesn’t work differently at different scales. What does work differently are some of the approximations we make do describe physics. There’s no scientifically accepted formula to describe a macroscopic process that works perfectly in 100% of cases.
You can apply Newton’s law of gravitation to calculate the orbit of a satellite, but the larger the orbiting body is, the less accurate they’ll become. At some point you need to switch to relativistic gravity because by then the Newtonian model is too far off to be useful at all.
It’s all a product of the way we explore the world and conduct science. We started describing the things we could see with our naked eye, and only then moved down smaller and smaller, into the atomic and then quantum scales. That’s not how the universe works, though, everything that happens is a product of quantum processes at the tiniest scale (and who knows, maybe one day we’ll realise it goes even smaller). It’s like looking at a cup of water and trying to come up with math to describe how it responds to outside forces. Yes, you can get pretty close, but you’ll never get a fully accurate model unless you’re going down to the smallest level and simulating everything that each little particle does. It’s those countless interactions that add up to produce the effects we see at our scale.
Also, physics doesn’t have rules
We observe the universe, find patterns, and then mathematically model those patterns
Stuff like the effects of gravity are super well understood and we can be extremely confident those patterns will continue ro hold true. We can’t be 100% certain, but pretty close
However, any day, we can find exceptions that throw out everything we think we know. As we get better tools and can observe more things, we can see more and more patterns which may go against patterns we were already familiar with
If you shoot a fly at a truck. The we can ignore the fly in the calculation of the truck velocity.
If you shoot a fly at another fly. You need to know the size and weight, and perhaps air pressure and humidity data, friction, compression of the body data, to properly calculate where the fly will end up after a collision.
If the fly is blasting through an electron cloud … does it even interact with the fly?
At each level. More detail is required. So our full understanding of everything isn’t clear enough for us to have 1 calculation for everything
Because some of physics is related to volume, some to area and some to distance. So if you scale something 100 times you have 100x distance, 10 000x area and 1 000 000x volume.
Or rather some values are squared and cubed and some not.
For example we have two balls touching each other. Now let’s scale them 10 times. 1000x more mass. 100x (r^2) less gravity force due to distance but 1000×1000 more gravity force due to mass. So 10000x bigger force is acting on a 1000x more massive object. That changes the behaviour a little
5 year olds wont understand the concept of relativity, in the sense of Duality. But, my explanation would be this: that person told you correctly. There is no rule anywhere. Its our choice of words (formulas, theories etc) that we use to explain what we see or experience. If you feel cold at 10celcius and i dont, then what is COLD anyways? Cold is a word which is relative – not real in absolute terms. What is ohms law? Well now we need to establish a common understanding of what we gonna call Ohm so we neet to set a “ruleset” for this concept. V=I.R is just words – its not absolute in any way or shape, its a common Wording we use to be able to communicate. Hence, physics doesnt work differently anywhere, it works however it works, but we call it differently. Weather is never cold, its just weather. Sometimes (at some scales, if you will) we call it Cold, sometimes we call it Hot.
It’s about probabilities at different scales.
If you throw a dice 6 times, it’s likely you won’t get each number once
You may get {6,1,3,3,2,4}.
I’ve got twice as many 3s as 1s here for example.
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However if I throw a dice 6000 times, the chances are that I’ll get each number a roughly even number of times (in terms of percentage differences).
The chances of getting twice as many 3s as 1s would be incredibly small.
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In both these examples, the physics of the dice doesn’t change – it’s just that at larger scales, the laws of probabilities are more apparent.
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This is why individual particles at the quantum scale can be hard to predict but large groups of atoms (such as a bouncing ball) are much easier to predict
It’s not PHYSICS that works differently. It’s our MODELS that work differently at different scales, which are imperfect, and therefore break down in certain situations.
Basically, our knowledge/mathematics of physics is incomplete, so we need to use a few “cobbled together” models that are the best we have right now.
BTW, saying “cobbled together” massively undersells the amount of genius and work that’s gone into our current models. It’s just that physics is even MORE complicated than that.
Physics works the same at every scale, however:
Some physical forces are negligible at larger scales (for example, surface tension plays essentially no role for an adult human) but becomes very much not negligible at smaller scales.
There are a lot of addendums to popular physics equations that, at normal human scales, end up at like *1.000000008, or otherwise don’t matter. For example we know from Einstein’s relativity that accelerating an object increases its mass, but it does that by such a tiny amount that when doing physics at *human* scale we can just ignore it, and stick to the old “F=MA” standby – you’ll be off by like a billionth of a percent and don’t care; but when working with interstellar travel then that error would increase enough that we now have to actually worry about it. The laws of physics didn’t change, but the error bars on our simplifications got big enough to worry about.
The same thing happens at very tiny scales – where we have things that at normal scale are ignorable becoming big enough to actually affect the outcome of your calculation. You don’t care about how the strong nuclear force affects the friction between a wheel and the road because it’s so small it might as well be zero, but you do care about strong nuclear force when doing fusion experiments.
If your computer was 1000 larger it would expand at least a meter, if not 10 meters when used, just because of thermal expansion. But, since it is fairly compact you don’t notice any of that, and the components inside are largely unaffected… except the tiniest bits where the scale is so small that is hard to understand and absolutely invisible to human eye.
Not very good analogy but i think it gets the point across. I could use Ohm’s law as an example too. It solves 90% of all problems in electronics design and repair but it is VERY much simplified and has about a dozen other parameters that we usually don’t care about as their effects are usually minimal. We can design quite precise circuits without using anything but two laws and yet, there is a lot more happening. Those things become increasingly more important when you want to push the specs close and closer to perfection. Like, a simple headphone amp can be done at better quality than your ears by just throwing components on a board that are roughly the right values but to make an analog null tester that can test it.. you really need to know a lot more about everything.
A piece of trivia: in 2018, i think, we finally were able to confidently have all units of measurement relative to universal constants, completing the “wheel”. But, as we did that some of the units needed to be fine tuned. So, current and resistance, iirc, changed a bit. No one talked about it since the change is in the scale of 10^(-7) and it really doesn’t affect anyone but maybe some theoretical physicist, and even then… insignificant.
The same laws of phisics apply to everything, however for a mosquito gravity has little importance while surface tension is very important, while at human scale the situation is reversed.
The laws of physics are, presumably, constant across all situations. However, while we can pretty accurately model macro- size systems (anything visible to the naked eye and larger), and micro- sized system (anything molecule-sized and down), our models for the two do not apply to eachother. Presumably there is some factor (or, more likely, factors) that we are not accounting for which would allow for one unified model that works across all scales, but that’s one of the largest frontiers in physics today, as I understand it
I think this person may be alluding to thermodynamic laws and identities.
We don’t have a method of predicting the behavior of individual particles in materials to absolute certainty. An example could be an arrangement of particles in some mixture.
Imagine that we have a room of regular old atmospheric air. The concentration of oxygen in air at sea level is approximately 21%. Logically, this would mean that if we scooped up some arbitrary volume of air at any location in the room and sampled it, we would get 21% every single time because the oxygen molecules are evenly mixed. But *why* can we assume that it’s evenly mixed? Why is it not valid to think that the oxygen can be significantly higher or lower in certain places in the room?
This is where scale comes into play. Imagine if we had a microscopic “room” with only 2 molecules of oxygen in it. If we allow these 2 molecules to float around as they will, it would not be absurdly unlikely for us to end up with areas of the room with “gaps” in it where there is no oxygen. This is because it isn’t exactly a huge stretch to think of just 2 molecules “choosing” the same direction.
This logic doesn’t apply on the macroscopic scale. There is no law *stopping* all of the oxygen from moving to one half of the room, but it is sooo statistically unlikely that we go ahead and assume that it is evenly mixed, because the odds of every single oxygen molecule moving in the same direction is absurdly small because you have trillions of molecules of oxygen in that room.
There are much more examples of how many of the “laws” at the macroscopic scale aren’t laws necessarily, but rather products of how statistical anomalies get “ironed out” by massive sample sizes.
Your friend may be talking about the disparity between quantum physics (very small sizes) and general relativity (large scale). We are unable to reconcile the theories, mathematically.
This is not because physics is different, its because we haven’t found the math to correctly describe it across the full spectrum.
Is everything an “estimate”? To some degree. Even using a gravitational “constant” on Earth as 9.81 m/s•s is not accurate (that’s an average value but not exact).
Do perfect circle and spheres exist? No. Pi goes to infinity (as far as we know) and at a very small scale, there isn’t any material fine enough to make a perfectly smooth surface. E.g. if you zoom in for enough the edges of any sphere or circle would be “bumpy” or eventually just gaps where elementary particles may or may not exist. On a large scale (human scale) we could make a circle or sphere that is “perfect” down to several decimals of Pi.
It doesn’t. The question is how much does it affect the overall picture. For example, if you are modeling fluid flow the interaction between the walls of whatever pipe you’re using and the fluid inside of it is about 10 microns. If you’re doing microfluidics and your pipe is 50 microns wide, 10 microns on either side is 40% of your diameter. At the other extreme, if you’re at a water treatment plant, a pipe could be 2 m wide. That 10 microns interaction is still there, but it is so small relative to other interactions that you can just ignore it.
Physics works the same no matter the scale. What your friend is talking about is the rules we use to describe physics.
Take Newton, he created some rules (laws) that describe Gravity as a force. Then Einstein came along and showed Gravity was actually bending of space time. Newton’s laws are still used today, as they work, we just use Einstein’s theory to understand Gravity more.
Currently the rules we have describe the large very well, and a separate of rules describe the small.
It makes sense that there is one set of rules that describe both, and we know we don’t know them yet, just like Newton did not know about the theory of relativity…
Physics works at all scales.
When you think of the Earth, you think of just Earth. But the reality is a lot, lot more complex than that!
What is Earth made out of? Mountains, Oceans. Land, Atmosphere etc.
What are they made out of? Rocks, Salt, Water, Gas…
What are they made out of? Smaller parts of rock,salt,water,gas in other words particles!
What are they made out of? atoms…
What are they made out of? protons, neutrons, electrons,…
What are they made out of? quarks…
What are they made out of? This is the question to which the official answer is we don’t know!
When we observe the Earth, our human eyes see it as just Earth, the big planetary ball. Once you look closer, you realize it is made up of millions of mountains, gazillions of rocks, particles,… down to gazillions and gazillions of atoms interacting constantly with one another.
Physics will work the same at any level. However, our calculations of physics in the bigger levels are at best only approximations, because we cannot keep track of each atom.
Very small (smaller than atoms) things behave differently from very large things. Particles are waves and waves are particles. A single photon can pass through two different slots at once. You can measure either the momentum *or* the position of an electron, but not both at once. Those things are not true for relatively enormous things like ball bearings and planets.
We can use quantum physics to predict a bunch of different possibilities for how large things *might* behave. But we need classical physics to tell us which possibility is the correct one…
So far, quantum physics and relativity have not been fully reconciled. This is probably because one or both theories is very slightly wrong. But since quantum physics only applies to things which are *very, very small* and relativistic physics only applies to things which are *very, very big (or fast)*, it isn’t really an urgent problem to solve. There are some theories but nothing that everyone can agree upon at this time.
Whether or not different sorts of physics *apply* to black holes and electrons… we currently need different sets of physics rules and theories to fully explain them.
https://en.m.wikipedia.org/wiki/Quantum_mechanics