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I’m Back!

DEAR LORD. It feels like it’s been forever hasn’t it? To all my followers, I am so extremely sorry about this. I, with the wise advice of one of my favorite teachers, decided to sign up for the AP Exams for history and I have been struggling for free time ever since. But now it’s over, and I am back. I will once again begin my journey into physics, especially with all this new found free time. I hope you enjoy!

John Smith

So what is mass? 

A very nice guy on PF corrected my definition of gravity on my previous post, and there’s no way I could reject it because I can’t define mass nor energy anyways. After mass today, I’ll probably head to energy once finals are over.

  • How heavy something is
  • How strong something is
  • How much energy something has
And, surprisingly, none of them are defining features of matter. Here’s the definition from George State University(which I’ve never heard of but I assume with degrees that they are much more qualified to define physics than I am):
The mass of an object is a fundamental property of the object; a numerical measure of its inertia; a fundamental measure of the amount of matter in the object.
So it’s a measure of inertia which is resistance to an acceleration. Now that I think about it, it fits together very well. Mass is the only thing that allows objects to control their speed at the cost of not being able to move at light speed. 

Let’s clear up the difference in the ambiguous school terms for weight and mass. Weight is defined at(by GSU as well):
The weight of an object is defined as the force of gravity on the object and may be calculated as the mass times the acceleration of gravity, w = mg. Since the weight is a force, its SI unit is the newton.
So weight is the force gravity exerts onto an object DUE to its mass(since gravity affects things stronger the more mass it has). Weight = Gravity’s force, Mass= resistance to acceleration. Moving on.

You might ask: sure mass, but why the dessert picture? That’s because mass is Greek for barely dough and I had no way to image ‘mass’ anyways. So there you have it. Mass means resistance to acceleration. And barely cake.

So what are the formulas?
M = e/c^2
W= Mg (because the formula for force of gravity is f=m1*m2/r^2 * G where G= 6.67 * 10^-11, and m^2(earth), G, and the distance turn into constant g which equals 9.81m/s^2)
Apparently there are different kinds of mass: Invariant, Gravitational, and Inertial Mass. So I’m going to read up on it and give the best possible definitions that I could give with my puny high school mind.
Invariant mass, also known as rest mass, is pretty much the energy or momentum of an object and/or its system. I’m guessing this means you’d have to use the mass-energy equivalence e^2 = (mc^2)^2 + pc^2 to get the momentum and energy. So converting m into p and e gets you invariant mass.
Gravitational mass is the part of the mass that gives the gravity field. Self explanatory, but this is not to say that gravitational mass is the ONLY thing that gives mass. I highly doubt that massless things(hence the name) have gravitational mass. Or maybe through the mass energy equivalence, momentum is turned into energy. So is energy the final thing that gives the ability for gravity to act upon it?
Inertial mass is simply the definition of mass as I gave it in the beginning: The ability to resist acceleration.
Meh, I’ll work on this later. I should probably study for finals now. I know IV League colleges don’t particularly care about GPA as much as SAT, ACT, or AP Exams, but I feel like if I get anything below an A on this one my parents will chop my head off.
Ciao!

quantumaniac:

Potential New Clock Measures Time Based on Mass

It’s part clock, part scale: A newly developed atomic clock measures time based on the mass of a single atom. The research, published online January 10 inScience, is controversial but could provide scientists with more precise methods of measuring both time and mass.

“This is the first clock based on a single particle,” says Holger Müller, a physicist at the University of California, Berkeley. “Its ticking rate is determined only by the particle’s mass.”

The idea for the clock stemmed from the quantum principle that particles also behave as waves, and vice versa. In particular, Müller and his colleagues wanted to determine how frequently the wave form of a single atom oscillates, a quantity that in quantum mechanics is inherently linked to the atom’s mass. Then the researchers could use those oscillations like swings of a pendulum to create a clock.

The snag in Müller’s plan was that it’s impossible to directly measure the oscillation frequency of waves of matter. The frequency of these waves is about 1025 hertz, 10 orders of magnitude higher than that of visible light waves. So Müller and his colleagues came up with an apparatus that creates two sets of waves — one based on a cesium atom at rest and another on the atom in motion. The researchers measured the frequency difference between the waves and then used that number, a manageable 100,000 hertz or so, to calculate the much larger oscillation frequency of cesium at rest.

With this approach, Müller was able to use the wave frequency of the cesium atom to create a clock that would gain or lose a second after eight years. That’s better than a wristwatch but about a hundred millionth as precise as today’s best atomic clocks, which count the frequency of light emissions from an atom as its electrons release small bursts of energy.

Physicists not involved with Müller’s research are impressed with his clever technique but are skeptical about its potential for precise timekeeping. “I think the paper is slightly oversold,” says Vladan Vuletić, a quantum physicist at MIT.

Other researchers have a more conceptual objection: Because there is nothing at this frequency actually oscillating within the atom, they say it is not a clock at all. “It may be a clock numerically, but it’s not a physical clock,” says Christian Bordé, a physicist at the Paris Observatory. Müller counters that the clock’s simplicity is its greatest trait: He is measuring an intrinsic quantum property of an atom, one that depends only on the atom’s mass.

In fact, this relationship between frequency and mass means Müller’s technique may prove most useful as a scale for measuring mass. Scientists define the kilogram, the base unit of mass, with a lump of metal stored in a French vault — a lump that is likely gaining heft from contamination (SN: 11/20/10, p. 12). The international General Conference on Weights and Measures, led by Bordé, wants to replace this artifact with a kilogram standard based on fundamental physical constants.

Müller says he can do just that by measuring the frequency of matter waves to accurately determine an atom’s mass. Once he finds the mass of one atom, he says, it is straightforward to relate it to the masses of other atoms. He will have a lot of convincing to do, but Müller plans to let the scientific process play out to test his ideas. “This is a concept that physicists never thought about,” he says. “This frequency wasn’t measurable until now.”

VERY impressive work. Keep it up! #Berkley

(via posits)

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WHAT IS YOUR FAVORITE INANIMATE OBJECT?

Nothing is inanimate because everything is moving through space-time at extremely high speeds on Earth because the Earth is rotating and orbiting the sun at high speeds.

Oh, you meant relatively? Books. They sit there quietly  and only talk to you when you open them.

So what’s gravity? You know, besides being the reason your fat rolls vibrate when you ride the bus.

Originally, Newton claimed that gravity was an invisible force between any objects with mass(but now we understand that he meant to say energy and momentum because otherwise light wouldn’t be affected, but it is and I’ll get to that later). The story is that an apple fell on his head, but that’s not really what happened, but this is another story for another time.

But Einstein more or less said that it’s not actually a force, but simply a dent in the space-time continuum. If you don’t know what that is, imagine this entire world like a graph. Just like the picture above. See that? That’s the space time continuum being affected by the gravity of Earth.  So because of the dent, you can imagine things falling towards it if it’s near it, like it would with a napkin and a coin. But unlike the tissue and napkin, once dented by gravity, the dent never truly reaches ‘equilibrium’ in the edges or even ‘outside.’ Gravity is omni-permeating and affects everything, and so things even light years away are ever so slowly ‘falling’ towards the dent. Of course this doesn’t actually happen because there are other dents in space as well. Gravity affects EVERYTHING and EVERYWHERE. That nebula you see light years away? Yup, it’s affecting you but the force is so minimal that it hardly matters. 

Note 1/12/2013 10:19 Central: http://www.physicsforums.com/showthread.php?t=663799

Somebody on the PF forums gave me their defining feature and definition of gravity. Here you go. I won’t be able to argue with this because I don’t know what mass is defined as, so I guess I’ll go into that next.

“Gravity is caused by the rest mass (and a tiny bit by the kinetic energy of a system) and affects particles with relativistic mass. Neither rest mass nor relativistic mass of matter cease to exist at zero temperature.”

You might say, “Well then why does gravity affect mass if you say gravity only affects energy and momentum?” This is because of the mass-energy equivalence, which looks something like this, you might’ve seen it before: e=mc2

Yes, e=mc^2 by Einstein. Of course, this is the incomplete equation. The REAL equation would look something like e=pc^2 + (mc^2)^2. So if energy = mass to a factor of the speed of light and energy equals momentum to a factor of the speed of light, the mass-energy equivalence basically states that anything with mass has energy, but not vice-versa. Light is a great example.

Light is affected by gravity, even though it’s massless. This is because it has momentum. This was noticed during an eclipse when a star behind the sun relative to Earth should not have been visible, because it’s you know, behind the sun. However, we can see that the gravity of the sun bent the light around the sun in its curvature of space-time. 

So why is gravity here? What causes gravity? Why just energy and momentum? Truth is, nobody knows. The most common accepted consensus is the space-time continuum explanation, but that still doesn’t explain everything. Some speculate that gravity is composed of massless particles called gravitons. However if this were the case, gravitons would have energy and would thus be affected by their own quantum field ‘gravity’ and ergo gravity’s force would infinitely exponentialize or they would both neutralize out and gravity wouldn’t be a force.

So let’s crash course what we just learned:

  • Gravity affects anything with energy and momentum.
  • It is a dent in space-time.
  • Nobody knows what causes gravity or why it’s here.
  • The mass-energy equivalency allows mass to have energy and thus be affected by gravity but not vice versa.

I also have a theory on absolute zero in relations to gravity and I’ll post it here in-case anyone is interested.

If absolute-zero is the theoretical state of a system in which the system reaches 0 Kinetic Energy, then it has no energy nor momentum. If gravity affects things with energy and momentum, does it cease to affect the zero system due to its lack of energy and ergo momentum? 
Of course I believe this is impossible to occur on Earth because the Earth is rapidly moving through the space-time continuum and along with everything else in it, so everything on Earth and Earth itself has momentum and thus energy so we will never achieve ‘absolute zero’ on Earth or anywhere else for that matter unless you can create a system in space-time continuum that ISN’T moving, which is completely impossible because according to Relativity, EVERYTHING is moving and nothing is not-moving. 
Or am I incorrect in my hypothesis in that absolute zero is only relative to the frame of reference it is in? And by that I mean that it doesn’t have to be not-moving in the universal frame of reference(I know no such thing exists but you probably get the gist of what I’m trying to say), but simply not moving relative to Earth or wherever the system is located?
There’s multiple problems with this but it’s a start. If an absolute zero system were ever to exist I believe it would be a key factor in solving the mystery of gravity. However, there is no experimental way to test this even if absolute zero were impossible because the only way to see if this works is to lift the system and see if it levitates because of the lack of force from gravity, but simply moving the system would give it momentum, thus energy, and thus heat and it will no longer be absolute zero. Or maybe we could make something hold onto the system in mid-air and let go? But according to laws of thermodynamics  as long as the crane or whatever’s holding it is holding the system, it will give energy to the system and thus the system will not reach absolute zero.

So I just found out that the above would be wrong because it’s SIGMA (summation) E= mc^2, not KE=mc^2, which is the only thing absolute zero would have minimal value in. So even without KE, there would be other energy, such as energy from the energy-mass equivalence from the mass. Thanks PF members for clearing that up. I’ll still leave it up there incase people want to see how I reached that conclusion.

Blah. My head hurts. More tea.

I’ll explore into mass or energy next, whichever I feel like doing. Or maybe matter. Dunno. Anyways, gonna snooze now. Ciao!

So let me journey into physics beginning with a lesson to the people who are (not) viewing this anyways.

I’d like to discuss my profile picture for a second. If you paid any attention in class to Mrs.Bender while she was giving her lecture on the atom in elementary school, you would identify the picture as an atom. I bet you’d also probably believe that the atom is a plethorical(new word!) clump of balls called protons and neutrons in the middle with electrons clearly and visibly revolving around the ‘nucleus,’ just like the picture above. Am I right? 

Alas, that’s not what an atom actually looks like. Really, it’s not even close. Allow me to show.

F Orbitals

I know that you’re probably thinking: what on earth is that? It might even be intimidating! Look at all those pink balloons!

Here’s the reality: electrons cannot exist the way you think they do. 

That is to say, it can’t exist as electrons perfectly revolving the nucleus ever so clearly. That’s not how it works. See, what would happen is this: if the electrons really did revolve like that, the electrons would eventually crash into the nucleus at close to light-speed almost instantaneously. I emailed an MIT professor about the exact time, and I quote: 

MIT Email

So basically, if that were the case then the INSTANT an atom of hydrogen came into existence it would explode in 100 picoseconds. That’s 10 to the negative twelfth of a second. If you still can’t tell, THAT’S SMALL. So why doesn’t this happen? Because Rutherford, the guy who came up with the whole planetary model of the atom that you see in my profile picture, was wrong. 

The way an atom can exist is through quantum mechanics. Big words, I know! But don’t be frightened! Simply put, electrons aren’t really like particles: they’re more like waves. I won’t get further into this, but if you’d like to know, then try reading about wave-particle duality here: http://en.wikipedia.org/wiki/Wave%E2%80%93particle_duality

And the truth about these waves? They actually exist in the ‘clouds’ that you see in the previous picture. Anywhere in those clouds, there’s a small set chance that the electron is there. Both the position and the momentum of the electron is UNCERTAIN. According to Heisenberg’s uncertainty, we have a uncertainty of both the momentum and the location. The closer we get to location, the farther we get from momentum and vice versa. Read more about it here: http://en.wikipedia.org/wiki/Uncertainty_principle

These clouds exist in ‘energy’ levels according to really, the atomic number. That’s the element number. I won’t get way into that either but it’s right here: http://www.kentchemistry.com/links/AtomicStructure/Sublevels.htm

All you need to know is that they exist in energy levels, and once you hit the first ‘orbital’ or energy level, you can’t get any lower and that’s why electrons don’t crash into the protons. There are 4 categories of levels: S, P, D, and F. The picture up there are all the possible F orbitals.

So let’s crash course what we just learned here:

  • The planetary model of the atom is incorrect.
  • Electrons actually exist in energy level ‘orbitals’ or ‘clouds.’ around the nucleus.
  • You can’t get any lower that level 1 so that’s why electrons don’t crash into the proton. 
  • We can’t simultaneously know the location and the momentum of an electron.

I know that this post was crappy, but this is my first time so cut me a break. I’ll improve! But I hope that you liked and more importantly, learned from this lesson.

I know it has nothing to do with the atomic model, but I will be diving into physics next post starting with gravity. Honestly looking back on it I have no idea what gravity is and I have no idea why it’s there, how it works, etc. So I’ll post my journey and findings then. Ciao!