mooeypoo

Obviously it didn't use proper terms, since multiple people have been telling you for a while now that you're making no physical sense. Instead of insisting you're right, try cooperating for a change and read the subject in question. I can promise you that if it won't help, it definitely won't hurt. We can't really continue like this when you just insist you're right despite everyone. ~mooey

We can't reference what you say becuse you don't speak an ounce of physics. We are asking that you go over a textbook so we can speak the same language when you criticize. What you're currently doing is criticizing swahili without when you barely know swahili and you do it in a different language. If you want to argue a physicist in their own court, you need to learn what that court involves. There's not much more to say, lemur. One person telling you X might have it out for you. Two people? Maybe they both have it out for you. But many people? You might want to take our advice at this point. Get a book and read the physics you criticize. We can't debate you otherwise. ~mooey

I support this request. lemur, before you can claim to revolutionize the way physicists talk and see concepts, you really should learn how physicsists *ACTUALLY* talk and see those concepts. You seem to have a view of what physics says that is too far from the real deal. I don't quite understand your reluctance to actually learn about the subject you're so keen on criticizing before you continue criticizing it. Are you interested in understanding reality, or are you interested in showing us all you're right despite not having physics education? You don't do much of reality explanation, whether you THINK you do or not. ~mooey

Meh, I always get those confused; Salt RAISES the boiling point, which is why it takes longer for saltwater to boil. Sorry. I get those mixed up all the time. BTW, thanks everyone for your help on this. It's very frustrating. Moontanman: I did read what the girl wrote, and I added a ton of salt (oversaturated my mixture) and it still didn't work. I'm starting to think you guys are right, and that the difference is too weak to actually see in the naked eye. Sadly, the "naked eye" (a thermometer) is the only thing I can use -- these are supposed to be home experiments, so no probes for me. If it isn't strong enough to measure directly, it's out. I'm going to have to try and think of another experiment showing different heat capacities. Maybe I'll go with oil and water, though I would rather not tell kids to mess with hot oil. Any ideas, btw, will be welcomed It must be a home experiment with stuff you can get in your kitchen (or can *easily* buy for relatively cheap). Thanks for your help! ~mooey

Salt lowers the boiling point of water, and the water SHOULD cool faster. Regardless, it seems we both agree there should at least be a difference in how fast they cool, and there is not so far.

Okay, this should've been very simple: Two cups with the same amount of hot water at the same temperature (75 Celsius). Add about 5 tablespoons of salt to one of those cups and stir until the salt is dissolved. Measure temperature of both cups. Wait 20 minutes, measure again. The salt-water SHOULD cool faster. I'm staring at those two cups at the moment, and they're both the same. Not only that, but this experiment says that the first two runs they did -- the temp dropped the same, and was different only at the third trial. WTF. Why does this not work? Salt should decrease the thermal retention rate of the water ... sooooo.... what's going on? Also, as a side note, if two times fail and once succeed, I wouldn't call it an experimental victory. Just saying. What am I doing wrong, can anyone fare a guess? They both have thermometers in them and are, after 10 minutes, stable on 50 degrees. Grr. ~mooey

A good start of avoiding this is to pose things you're uncertain about as a question rather than a statement. Weight is a force (Gravitational force) and Voltage is an electric potential difference, so in that aspect I'd just be careful in the similar-framing. But in general, I guess you can think of it similarly in terms of conceptual imagining of the effects; To get gravitational potential we can use the equation [math]W=\int F \cdot dr[/math] (which leads to mgh on earth) To get electric potential we can use the equation [math]V=\int E \cdot dl[/math] In that aspect, they're similar. Just worth noting also that electric potential will only act on objects with an electric charge while gravitational potential will act on all mass. ~mooey

Okay, enough,this isn't a "beat on the people who are trying to help you" forum. Thread closed, and I suggest you re-read my previous and previously-previous post. Seems some sarcasm might be in order here for you. People here spend time and effort to answer you. A "thank you" might be too much for you; I suggest at least stop offending the people who do that for FREE for you. It's not about accepting answers blindly, it's about not being so damn rude to people who TRY to help you understand concepts you don't care to even try to cooperate with. So let me finish this thread in the good note it should receive: You're welcome. Thread absolutely and utterly closed.

You don't seem to want to participate in accepting answers, you want to be fed simple answers that fit your view without taking the time to learn anything extra. There are a few posts in this thread that offer some really good textbooks to allow you to learn more. Are *you* interesting in learning? Maybe you should go over my previous post some more before you so callously try to piss in the well you drink from. ~mooey

! Moderator Note SSDS, this is a mainstream physics thread, requiring mainstream physics answers. Do not hijack the thread with speculative subjects. If you want, you're welcome to open your own thread in the speculation forum and discuss why the "absolute frame" is the next best answer to this current question.

Another question -- is the exercise specifically asking to factor this, or is the exercise meant to solve this? There ARE ways to solve a polynomial without factoring it. Another hint - before you try to factor, try to see if you can reduce this equation somehow. Show us some of your work and we can continue to guide you.

Wow, I never thought of watching YouTube videos to answer all my physics questions. Please, go watch these informative and non-interactive videos and obtain a virtual PhD-equivalent level of knowledge of the entire operation of the universe without the need to ask a single question. In fact, please come back to us afterwards so you can help us instead. Because you're right, how silly it was of swansont to go all complex on you; physics is never complex at all! It's all simple and clearly stated and never anti-intuitive or mathematical. Ever. All those PhDs who spent years getting an expertise are just pretending to study. In reality you can simply absorb the knowledge to each physical subject by reading a single answer post in a single forum thread and by watching two or three YouTube videos. You don't even have to have a single college-level physics class, because it will all just become so clear after you watch the blurry CGI effects on YouTube. It should be an accredited University. Do tell us how brilliantly done those huge amount of physics videos are, since you will, of course, understand the material so well afterwards you will have no questions at all to ask. It will be so clear, you might as well earn an entire theoretical physics PhD in an hour. Swansont was just trying to confuse you on purpose by wasting his valuable time sitting down and reducing a complex subject to something a non-college-physics-level student can conceptually understand. Shame on you, swansont. We will make sure to notify our volunteer experts stop wasting their time, too, since obviously taking their valuable time to try and answer people's questions and try to explain complex concepts that usually require years of study to forum-posters who have barely any college level physics is so ridiculously simple, it's just a waste of their time. We should ask those wonderful people from Yahoo! Questions to instead come and text you theoretical physics concepts in 140 characters or less. We're onto you, swansont. ~mooey Disclaimer: Please remember to wipe your screen after reading this message. Large quantities of sarcasm are known to corrode screens and young minds.

Lemur, sometimes you're plainly wrong. I understand that you're searching for answers, but you seem to insist on being so defensive about your own point of view, it tends to make the argument completely moot. Either you want to know what mainstream (workable, testable, empirically proven) physics say on the matter, or you wish to stick to your guns and play allknowing. There's nothing wrong with being wrong. There's a lot wrong with insisting you're right when the evidence is against you. This wordplay games and defensive redefinitions are really unhelpful here. Getting things wrong is how we learn. ~mooey

There are many tricks and illusions that seem to make sense and are still bunk. How would you propose we sift through what SEEMS true (but isn't) to what SEEMS unreal (but is) without some empirical data? Calculations, mathematics and physical theories with evidence, observations and repeatability are meant to supply exactly that - a consistent method to know what is real *despite* what might *seem* real to us. I can give you a dozen examples of things people think are entirely reasonable but are, in fact, false. The most notable one is "the world is flat". The only reason you might consider this no longer reasonable is because of CURRENT knowledge and satellites and spaceflight, etc. But 2000 years ago, the laymen would undoubtedly argue the scientists who said the world is spherical, since the laymen, walking out and looking at the horizon, saw flat surface. If we were to accept "logic" without empirical evidence, we'd be still afraid to fall off the edge of the Earth. ~mooey

Potential energy is just that, potential energy. It's the energy the object potentially could have with respect to where it is. Hence our insistence on it being dependent on "arbitrary relative position". Any object at any time has multiple options for its potential energy, that's what I was trying to convey with my example. My phone, for instance, is sitting on my table right now. It can be said that it has no potential energy because it's at rest relative to "zero" position (the table). But it also DOES have potential energy if I think of my chair as the "zero" - and I could use conservation of energies to figure out what velocity it would have in case it fell off and hit the chair. But then, I'm also at the fourth floor right now. My phone, theoretically speaking, has the entire height of the four floors AND the height of my desk as its potential energy height at any given time, if I take the ground floor as my "zero". It's relative and chosen arbitrarily because it's not really usable energy until you actually drop it. It's energy that is only usable when it's converted, really. If an object remains at rest somewhere, it can have all sorts of "potential energies" that are meaningless until you find one you want to use when it actually moves somewhere lower or higher. Therefore this statement: -- is meaningless. Potential energy exists out of definition of it. On one hand everything has potential energy relative to some arbitrary point that is not their own position, and on the other everything that doesn't move is at zero potential energy relative to their own position. The only place where you have use of this energy is when an object moves. The problem with Relativistic movement is, among other things, that the mass changes and the velocity is relative (.. hence 'relativity'). Also, General Relativity deals with different gravitational issues and that affects the "gravitational potential energy", obviously. I must admit that General Relativity is NOT my strong side, so I will have to rely on one of the other physicists to assist in explaining this further, but the general idea is that 'potential energy' is, quite empirically proven and working, depended on arbitrary position that are absolutely relative to the object and MUST be in the same frame. If they're not in the same frame, then the relative position is moving with relation to the object, and you lose your whole definition. The entire point is that "potential energy" is, by definition, whether you like it or not, exactly what it is defined to be. By the way, you should read a bit about the derivation of the formulas. It might help you understand why it's defined the way it is, and why we insist it's dependent on the frame. Also, lemur, you speak about empirical things but you don't give empirical data. See, empirically, there's no meaning to what you're saying, really, and in order for it to have empirical meaning, you need to supply empirical evidence. Say, a calculation that works the way YOU describe the problem. The calculations in special relativity aren't difficult at all, so this should be relatively easy to check if it *actually works*. can you give us an example of where potential energy exists regardless of the definition of it? ~mooey

Sorry, chem isn't my strong side. Can you explain (or point me to the direction of more data)? Also, does that mean that ANY heat would do this? not just "burn" ? I shall try.

Oh, good point, didn't think about that. Thanks!

Lemur, we're dealing with definitions here. Potential energy is defined by arbitrarily chosen (but *consistent*) relative points. That is, if I stand on a 1 meter chair on top of a 10 story building and jump off the chair, it is my choice how to define my "potential energy" comparison point, but this point MUST be consistent later. I can choose that my "zero" is the ground (at the bottom of the building), in which case I started with potential energy of mg(10stories+1meter) and ended with potential energy of mg(10 stories), and the difference is just mg(1 meter). Or I can decide that my "zero" is on the floor relative to me, that is on the floor of the 10th floor -- in which case I started with potential energy mg(1 meter) and ended with mg(0), which makes the difference again mg(1 meter). The only time a potential energy is not really arbitrary is in the case of potential elastic energy, where the "zero" point is considered the equilibrium resting point of the spring. That's the way we define potential energy. It is, therefore, dependent on a location in the same frame it's being measured. By definition. I am stating a bit of simplistic stuff here, but you should really pick up a physics book for the more elaborate concept; this "pick up a book" deal isn't to condescend you. It's to help you understand. Before you try to revolutionize physics I think you probably would do best to learn what it actually says on the matter... ~mooey

Yeah the explanation that keeps reapeating is that the acidic lemon juice weakens the molecular bonds of the paper. So later when it's burned, the parts that were "dyed" with the lemon juice would burn quicker (and darken quicker). It was just a bit odd to me, and I wanted to make sure that's the right explanation.

Aye, but both of these require evidence. If someone provides the evidence, the textbooks change. We see that happen quite often. We require actual evidence and workable predictions to explain why the textbook (and by this we usually mean 'mainstream physics') is wrong. Without actual predictive work and evidence, no one will replace the textbook. There's a difference between a textbook being too vague or having statements that a reader misunderstands or not good enough to explain things -- than mainstream physics being wrong about the definition of a concept. The first just requires extra help *understanding* the real concept. The second requires evidence and some work to show that current work is lacking or untrue. In any case, no one will accept "conceptual explanations" without mathematical predictions to replace the current work that *has* mathematical prediction, works wonders and is actually showing itself to be repeatedly true. ~mooey

I'm trying to write-up an activity sheet about the "invisible ink" experiment with lemon juice. For those who are not familiar with this -- you take lemon juice and use it as ink to write a "secret message" on a piece of paper. You wait for it to dry up, then when you're ready to read it, you heat it up. The juice becomes brownish. I want to explain WHY this happens, and I can't find any good resources. I keep reading the explanation that the lemon juice "weakens the paper" and when you heat it up the previously lemon'ed parts burn faster (hence turning brown). I am skeptical of this explanation, it sounds weird to me.. if that's true, it would happen on an open flame and not, say, heating by lamp. And yet it DOES happen when you put it on a hot lamp. Is this some chemical reaction due to heat? What's going on here? Anyone? Is it true that the message on the paper is just "burning faster" than the rest of the paper? Help.. ~mooey p.s, here's an example of this experiment and the proposed explanation http://chemistry.about.com/cs/howtos/ht/invisibleink3.htm

Hiiii Bettina! Good to *** see you *** come back.

Because it isn't; the math is an underlying layer of the "concepts and ideas". The fact you don't understand them doesn't mean they're not true. You were asked to pick up a physics book so that you can see it for yourself and learn a bit of why the explanations are what they are. You can't refuse to cooperate and then claim the other people are ignorant, lemur. Now, please get back on topic. There was an actual question asked, and the discussion was moved to other questions instead. ~mooey