Quantum Physics

For a very basic understanding try checking out "The universe in a nutshell" or "The theory of everything" by Michio Kaku on youtube. It's more theoretical physics but it's a great intro to the general field

[ame=http://www.youtube.com/watch?v=0NbBjNiw4tk]Michio Kaku: The Universe in a Nutshell - YouTube[/ame]

also, have you looked at the list? http://forum.grasscity.com/science-nature/272678-anyone-interested-learning-anything.html

 

I'm going to pit this as simple as possible to help you and anyone else getting started in this amazing field of science. Quantum physics is the physics of small things, literally speaking. Many years ago scientists discovered big matter our world behaves differently than the atomic world). Einstein, in his theory of relativity, showed how matter and energy worked in our world but his equation did not apply to the atomic world. The biggest reason the atomic world is so strange is because atoms sometimes behave like particles and sometimes behave as waves. http://youtu.be/DfPeprQ7oGc Watch that video and you should have enough to get started also search quantum entanglement for more interesting research. Hope this helped to get you started any questions just ask.

 

Neil Degrasse Tyson can explain it to you. Look him up. He is the man.

 

The best way to get an understanding of any field of science is to follow its progress through history. That way you're forced to start with the simpler stuff and work your way up to the huge clusterfuck that is modern physics.

Start with the Double-Slit experiment. If you understand the double-slit experiment, you understand the basic problem with classical physics (ie that matter and energy are the same thing...or at least spring from the same potentiality) and why the discovery of quantum physics calls for a real conceptual shift in nearly all human knowledge, not just a new branch of physics. On the contrary, if you don't understand the double-slit experiment you sure as shit don't understand quantum physics, so yeah....start there....and don't move on until you really get it....

 

A large part of quantum mechanics is based on diffraction of light - aka it being particle and wave.

If you have a slit and a laser beam going through it and start to make the slit narrower and narrower the light beam passing through and being projected on some surface becomes smaller and smaller.Then at a certain point it starts to fan outward!
This is crazy!
This is the uncertaintly principle in work! deltax*deltap is >or= hbar
hbar is a constant, deltax is change in X direction, and deltap is change in momentum (in x direction) and hbar is a constant (very small).
Basically, as the slit becomes too small, the x direction is limited - but this relationship has to remain true. So when the photons are restricted in how much they can move in the X direction, their momentum in the x direction has to increase to make up for decrease in x. When momentum goes up, the photons fan outward - creating the diffraction we see.


That's a small part. And i cant remember if its hbar or hbar divided by something...

I'm taking quantum mechanics this semester - along with p-chem, it is probably one of the hardest courses offered at most universities. My two classmates and I are all struggling to grasp the concepts and the math that goes with them... It's a really cool topic though.


Another large aspect of quantum is that energy levels are discrete, or quantized. Without going into too much detail, it means that the energy levels jump at certain intervals.
So a completely made up example that shows the point is lets say that at its lowest orbital an electron has 2eV of energy, the next step up to the orbital above is 3eV. This electron will never have 2.3eV or 2.6eV - it will either accept 1eV (via a photon) and make the jump or lose 1eV and drop from 3 to 2.

 

the fist example you give makes me think of how water reacts under pressure when im watering my plants with the garden hose and turn the hose nozzel fitting to tight.

 

Quantum mechanics and physics applies to very small objects (on the scale of nanometers or less: one nanometer is one billionth of a meter). With objects this small, different forces become more important than we are used to, and matter behaves in a manner we are still trying to understand and explain. This field of study is far from complete and thourough.

First let me explain what quantum means. It means things are quantized (stick with me here) meaning that there are discreet states that are accessible and the rest of states are forbidden (or inacessible). Imagine it like this, you are driving 20 MPH, then you accelerate to 21 MPH. How many different speed increments were there during your 1 MPH acceleration stint? The answer is infinity. You went 20, then 20.1, then 20.11 MPH, until you got to 21.00000 MPH. You definitely do not go from 20 to 21 without being at 20.5. So your speed is not quantized.

Atoms all have electrons, and these electrons can absorb energy from photons. When an electron absorbs a photon, it absorbs energy, and so gets excited to a more energetic state. This process is quantized. In other words, an electron will go from here to there without ever being in between. It's like teleportation. You were here, then you INSTANTLY went over there, without ever occupying any of the space between here and there. Hydrogen for example, like any other atom, has characteristic absorbing and emitting frequencies. Hence a light spectrum of hydrogen atoms will have missing or individual lines in the place of absorbance or emission respectively. In fact this spectroscopic technique is used to determine what stage of the lifecycle a star is in. (Stars initially fuse hydrogen to helium for energy, so the presence of hydrogen indicates a young star)

An atom is over 99% empty space, meaning that everything we know of (water, rocks, glass etc...) is over 99% empty space. When I say empty space, I do not mean air is there, I mean there is NOTHING between an atoms nucleus and its electrons. Theoretically its a vacuum in that empty space. Boggling.
Electrons in an atom are represented not as particles like you would think, but as waves. Electrons move so fast that you can never know their exact location and velocity, so we model their molecular orbital paths with wavefunctions.

Quantum mechanics is a huge field and there is a lot more to it than the wave-particle duality theory, but it essentially forms the fundamental basis. Electromagnetic waves behave like both waves and particles. These waves can interfere with eachother like ripples in a pond, have frequencies, and amplitudes,and phases, which are all characteristic of a wave. Yet these waves are transmitted by photons, a type of light carrying particle (boggling again), which is characteristic of, well, a particle.

 

Quantum physics is insane.

Nassim Haramein is my favorite physicist.

He does a great job explaining and tying theories together.

 

empty space in particles? or unperceivable matter since our brains arent wired to see it?or are they......

 

Back in the day...physicists looked at things and made determinations about the nature of their interactions with other things.

Then one day people came along and said, "what if we convert all things to numerical quantities instead of just having all these random novel things?"

So they did. The idea being that they'd be able to come up with better predictive mathematics by having a more precise understanding of how everything worked by applying numerical quantities to everything.

Now physics is predominantly the endeavor of attempting to explain novel physical observable phenomena by way of creating mathematical maps of everything so to speak.

The fundamental problem with it is zeno's paradox. Infinite divisibility. At some point of another you've got to choose a place where the decimal stops. When you do that you essentially create uncertainty because you can no longer explain things that are smaller than your unit of measurement. There's an inch, but we don't know what's underneath that by simply referencing what quantification theory can tell us....we have to go back and look at the object and actually observe it once we exhaust all things we can know about it based on numerical measurements.

Think about a scale for weighing weed. If it goes just 1 decimal place, then when it says "5.0g", it could really be 4.96g, or it could be 5.04 grams. Both would just say 5 grams because we lack the ability to observe anything smaller than a .1 gram with the scale and we know that it's going to round up and down. That uncertainty in exactly how much weed on the scale is quantum uncertainty.

 

The interpretations of quantum physics are even more interesting than the mechanics themselves.

All of them encounter conscousness

 

Joseph had the best explanation on here, and was in the right direction. Anyway, unlike everyone who is focusing on the double slit experiment, which is very important, quantum mechanics is literally the concept of quantizing. It means that we can COUNT states that have information pertaining to a system, rather than them being continuous (continuous we CAN'T count things, there are an infinite amount of numbers between 0 and 1!). There's a lot to it, anyone can learn it, it will just take a lot of work.
 
Also, an interesting fact for those who are talking about empty space. You should look up something called the Dirac Sea. You'll find that our space is not so empty, and in fact, we can create electron-positron (electron's antiparticle) at ANY point in space. How's that for strange... The explanation for why electrons don't fall to minus infinite energy was explained by saying that space had electrons and positrons that occupied all of the negative energy states. But that's just a small tidbit about the vacuum, we know hardly anything about it, yet we know it's definitely not as empty as we thought.

 

http://youtu.be/dbh5l0b2-0o