In an article published on May 20 in Science, the researchers therefore refuted Einstein's argument regarding Brownian motion
Brownian motion was named after the Scottish botanist Robert Brown, who in 1828 published detailed observations about how tiny pollen particles soaked in water can be seen to oscillate and wander when viewed under a powerful optical microscope. When Robert Brown looked through the microscope at the tiny pollen soaked in water he wrote, "I observed many of them very clearly in motion... [these movements] did not arise from currents in the liquid, nor from its gradual evaporation, but belonged to the particles themselves." To make sure that the pollens are not alive - and actually floating around - Brown tried the experiment with coal dust. Dust had the same movements. The study was repeated with the help of other particles, and a variety of explanations for the phenomenon were proposed. Perhaps, they thought, the phenomenon had something to do with tiny currents of water or an effect of light. But none of these theories made sense. With the rise of the kinetic theory of gases in the 1870s, which used the random motions of molecules to explain the behavior of gases, some tried to use it to explain Brownian motion. But because the water-soaked particles were about 10,000 times larger than the water molecules, it seemed that the molecule would not have the power to move the giant particle.
Einstein's paper on Brownian motion was published on May 11, 1905. Einstein relied on a statistical investigation of the random actions of particles to show how they manifest in the macroscopic world. In doing so, Einstein explained the Brownian motion that had been troubling scientists for almost eight years at the time: Why do small particles suspended in a liquid like water seem to be moving around? And as a byproduct Einstein established once and for all that atoms and molecules actually exist as physical objects. Einstein showed that even though a single collision cannot dislodge a large particle, the effect of millions of random collisions per second can explain the random frenzy observed by Brown. "This article", he announced in the first sentence, "will show that according to the kinetic molecular theory of heat, there are microscopic-sized bodies inside the liquids that must, as a result of thermal molecular movements, make movements of such sizes that they can easily be seen with the help of the microscope."
Einstein said that it is impossible to determine at every moment the speed and direction of the particle during its random motion. Einstein realized that a hit from a single water molecule would not cause a pollen particle suspended in water to move enough for its movement to be visible. However, at any given moment, if thousands of molecules randomly hit the particle from all sides, then there were several moments when many more hits happened to hit a particular side of the particle. And then, at another moment, another party could receive a heavier rain of vulnerability. The result will be small random oscillations that will cause what is known as a random walk. The best way to visualize this is to think of a drunk walking. Statistically, the drunk's distance from the starting point is equal to the square root of the number of seconds that have passed, not to the number of seconds that have passed. Einstein realized that it is not possible and it is not necessary to measure every zigzag of the Brownian motion, nor is it necessary to measure the speed of the particle at every moment. After all, the particle is moving too fast for us to measure its speed and direction. But it was fairly easy to measure the overall distances of randomly oscillating particles as those distances increased over time. When we finally present this result in a graph, we get a typical bell curve.
The researchers led by Mark Reisen found a way to attack the issue of measuring the instantaneous velocity of the particle in Brownian motion by converting the problem from investigating particles in liquid to particles in air. Air is less dense than water, so its molecules are further apart. Hence the distance and time between the Brownian collisions is greater. But then a problem arose: air cannot support the lightest particles against gravity. What to do? The group took a bead of silicon oxide, or if you will silica glass, the entire size of which was on the order of a few microns. How does it float in the air? The group took a transducer that activated ultrasonic vibrations that shook the beads straight into the air and optical tongs that captured them, a pair of laser beams that applied radiation pressure to the beads. When the bead was in the air molecules of the air bumped it back and forth and moved it slightly from the center of the laser trap. This deviation from the center of the trap was measured by the difference in power between the beams. The researchers fed the data from the measurements into the experiment: how the position changes with the time variable measurement. They found that on a time scale of microseconds this ratio shows that the distance of the Brownian particle from the exit point is equal to the number of seconds that have passed. They then calculated the instantaneous velocities from the simple formula, time divided by distance and found that the velocities follow a Maxwell-Boltzmann distribution, as the kinetic theory predicts. The researchers were thus able to determine what Einstein considered impossible in 1905, the momentary speed and direction of the silica glass beads.
For the abstract of the article in Science
More on the subject on the science website
61 תגובות
Amichai-
To give a completely accurate answer you need a little more than a few lines. But let us try to give an intuition; Assume for simplicity that the particle can only move left and right (this seems limiting, but also in the more general case the same idea that will be described below works). At any given moment, a random force acts on the particle that causes it to move one distance unit to the right or to the left in each unit of time with equal chance. Now the question arises, what will be the average distance of the particle from its point of origin after n units of time? The squared distance is 2^(X_1+X_2+…X_n) where each of the X's appearing here can equal 1 or -1 with equal chance. If we take an average over all the possibilities we will get that the squared copy is equal to n, and hence the distance is proportional to the square root of n. As I mentioned, the concept in three dimensions is similar (although it's a little more complex to see).
Right 60
A. Ben-Ner - Get Ah Life, Man!
For someone who usually just reads here I have to say that it was very entertaining to read this stupid and pointless rant.
On the one hand, the commenter "A. Ben Ner" made an unprecedented attack here, and in my personal opinion also pointless, at least for me.
But the truth is that I can also understand him, even though I personally did not notice such a big difference between an article and an article here, if he is used to a certain standard, he is allowed to give criticism, it can be sharp, but an attack like here is an exaggeration, to go and find personal details even as proof of a claim (the download of the resumes and reading their content here, definitely give a fair bit of justification to his claim) for me personally it's a waste of time.
Regardless of the legal aspect, someone here wrote that everything on the web is under copyright, which of course is not true, or rather not exactly true, every work or image has a certain protection under copyright, but there are also specific criteria that must be met and I highly doubt that the resume on the site is open Everyone has a problem with them, even if it is claimed that he violated her privacy, there is no proof of damage because he did not distort or change anything, he did so under proof (this can be defined as an example of the writer's ability to meet the site's standard) for a claim under an article she herself wrote on this site.
The smarter thing legally would have been to give a link to the page where the resume is on her website.
But again even writing this comment was a waste of time.
The only thing that is not a waste of time is my last words to Mrs. Gali Vinshet. Well done to you and thank you very much for volunteering and helping and writing on this site. I wish there were more people like you.
Getting really funny here.
I didn't expect that my lovers would move into an apartment with me
Maybe it's worth explaining once to the readers what scientific writing is: the science website provides you with scientific news in Hebrew. There is a lot of news that appears here on the site that you can't get to because it takes skill to find it. And the reason is that you do not know the correct science channels in which they are published. It's not just that we translate news. Not at all. We bring you this news in articles of 800 words and maybe 1000 or so maximum. Summarizing scientific news in 800 words is very difficult. We will see you Mr. Ben-Ner summarize a scientific article from a journal, an article that is 4000 words long including the articles that explain the article that is 3000 words long, all together you will summarize in 800 words. It requires a lot of experience. And that is the length of a journalistic article, even preferably less than 600 words. In addition, a journalistic article has its own language - a special language. And this is not always the language spoken in a physics lecture room. The terms are the same. But there are slight changes because this is journalism. This is journalistic news addressed to the general public: scientists, interested readers, etc. Also, the scientific journalist must take into account what the public understands? What does the reader know about science? What does he know about NASA? What is his level of understanding about launching a spaceship? The writer thinks about the reader and the terms he reads in the original article.
Ben Ner, if you have any objections to the content of the article, present them here. If you have any doubts about the writer's personality, write a private email to Mr. Blizovsky or Dr. Weinstein and receive a reply. It is not proper to vilify a person in public if only because of the slim chance that you are wrong.
A. Ben-Ner:
Please tell me what all this has to do with the discussion here.
Dr. Gali Weinstein claims that her main field of expertise is "science teaching".
I am not familiar with the formal specialization tracks in the field of science teaching, but I can certainly imagine a situation where someone would receive such a certification without having a teaching certificate.
Just for the sake of illustration - a person can be an expert in teaching science, but it is certainly reasonable to require someone who is applying for a teaching certificate - to know Hebrew, or not be mute and paralyzed in his hands.
Someone can even get a teaching certificate abroad and this certificate will not be valid in Israel.
There are all kinds of situations whose very existence justifies the separation between a teaching certificate and specialization in science teaching.
Note - I am not judging the facts themselves but only the basis for your claim.
Beyond that - I repeat and ask - why did you find it appropriate to talk here about the resume of Dr. Gali Weinstein instead of being content with attacking her claims that you do not agree with
A. Ben Ner So far I have hardly intervened, but yesterday I announced that if the attack on Gali continues, I will delete any such comment.
Please spare me the need to delete, just stop the attack.
with gratitude
Avi Blizovsky
A. Ben-Ner:
The criticism of the content can be left as a criticism of the content.
I too had reservations about mixing Einstein's name into the matter and that is exactly what I wrote.
If you read the sources mentioned in response 3 - you will see that they all sinned in the same matter.
Therefore - even though I also think this is "blasphemy", it is clear that the source of the blasphemy is not in the translation and extracts but in the foreign sources.
Regarding the resume - I really don't understand what you want.
There were mistakes in the resume published on the website of Dr. Gali Weinstein herself.
You pointed out these mistakes.
Dr. Gali Weinstein took down the wrong resume - either for renovations or because she decided it was better not to publish it (and that is her right too).
You really used the details on the resume without permission.
As a principle - it is accepted that everything that is published on the net is subject to copyright and this also includes the resume.
Copying the text verbatim without indicating the source really constitutes, therefore, a violation of copyright.
In my opinion, there was really no place to mention this fact as a reason for downloading the resume from the website, but factually it is probably true. Anyway - this is a debate that has heated up beyond what is necessary and I really think it should be stopped.
To Michael
A]. Without going into the definition of the concept of "expertise", nevertheless something in this article stood out
In my opinion compared to the standard level on the site.
B]. I will try to explain briefly:
The usual translations and abbreviations published in "Hidan" are faithful to the original to a large extent
And this is the policy of the writers and translators.
In the article in question, however, the emphasis was not on the discovery itself but on the pseudo-sensational aspect
Artificial and careless, as if an important scientific-Einsteinian principle collapsed and fell.
The author preferred to emphasize herself and the presentation of the most marginal aspect of the subject, instead of the discovery
the scientific-technological itself. In my opinion, the wording is also inflated, cumbersome, unnecessarily long and troublesome and it is not
Typical of the other articles in "Hidan".
D]. What brings me to add and think that there is at least a pinch of truth in my words is what now appears on the website
the writer The resume that was there, was deleted and there was no prison. In its place now appears a note that the details have been deleted
Because they were allegedly published online without permission.
For the sake of accuracy, it should be noted that the notebook's website states that the articles appearing in it should not be used without
Author's permission.
There is no ban on citing her academic resume.
Is the academic resume of the notebook a secret?
Is a person's academic-professional resume intellectual property subject to copyright?
It seems to me that the answers to the last two questions are negative.
A. Ben-Ner:
We all love the site, but let's face the truth: a large part of the articles that appear on it are not written by experts in the research subjects that appear on it, but by volunteers who have gone to the trouble of translating articles written in the professional press or on other popular science sites.
A large part of the translations is done by my father himself, and he also translates and summarizes articles that are certainly not in his area of expertise.
That's why your insistence on Dr. Gali Weinstein's CV seems out of place.
Even if she wrote something that you don't think is in her area of expertise - that is completely legitimate and the criticism - if any - should be directed at the things themselves and not at the writer who was trying to do us all a favor.
Dear Friends
A]. In my previous comments, I did not bring the resume of the author of the article, but only the professional resume
- Its academic and it is definitely relevant.
B]. The resume I brought was not the result of an independent and proactive investigation that I did, but rather, a quote=copy from her website. This is exactly what she wrote about herself and what she chose to publish publicly on her website.
third]. What made me enter the personal website of the author of the article and learn about her professional-scientific record was, and I say this very carefully, a certain impression from reading the article below.
Something in the way of expression, phrasing, and the level of presentation of things seems to me...how to say...?...
Raised my skepticism... And it's enough to be wise with an allusion.
D]. I believe that it is appropriate for experts to publish articles that are in their field of expertise.
For example, if so-and-so or anonymous are experts in the subject of the history and philosophy of science, it is appropriate that they bring articles dealing with the subjects of their specialization and not precisely articles on the subjects of contemporary scientific discoveries in which they are not experts... this is evident and the difference is clear.
Happily, this has been the way of the "Hidan" site since time immemorial and this article is an exception, to the best of my understanding and judgment.
ha (:
The truth is, I expected this to be what you would answer, even with those exact words.
I did not raise the issue of Zvi Yanai because I sympathized with the defense of Gali.
In my opinion there is no point in digging into someone's life history and one should judge people's words according to their content.
Since the issue of Zvi Yanai has already come up, I will only say that I share Ehud's feeling about it.
However - even if he wrote an article here that I do not agree with - I would try to deal with the content and not with his biography.
Ghost:
Is it me or did I read your express request to censor most of your comments?
Ben Ner
Regarding Moshe and S, it was accidentally messed up. It's just that when I answered them in another article, the comments were deleted, so I wrote it here, but I forgot that the discussion was in another article.
I am not rude, but defend my good name against any bad name that tries to defame me.
Apart from that
Avi,
Maybe think of something and do something that will prevent the comments from browsing to things unrelated to the article, please?
Maybe someone in your system will filter the comments that are not related to the topic of the article?
It is intolerable, when trying to understand a certain topic, and the discussions slide into topics such as: ultra-orthodox, the resume of Dr. Weinstein and the like.
Thanks.
Ehud, Zvi Yanai is not the issue here. I rebelled against the audacity of publishing the author's resume in Talkback and then further questioning her about how it is possible that she is employed here or there. I don't think it's appropriate at all.
And it seems to me that from now on any such response, especially from anonymous ones, will be deleted.
Amichai
The connection to the heat equation is that the random motion of the liquid molecules gives the Brownian particle its random motion.
R.H.
I don't usually slander people, but I say that I am not impressed with Yanai's situation, he does have extensive knowledge, but he also has an inflated image and is full of self-importance. Although Hanai has never dealt with science, he pretends to know more than researchers who do deal with it, while his main knowledge is popular science...
A. Ben Ner and the other debaters on the author's resume. Did you exaggerate a bit? I suggest that you post your resume and identify yourself with your real names and then we will discuss the merits of each of you's achievements and your right to comment on the subject. Scientific degrees are not always a measure, see for example the case of Zvi Yanai.
A. Ben Ner - It is true, I am of Polish origin, but I do not see myself as a knight protecting my waves. Note that she studied other things besides theater art. The courses she gave and you are surprised about them are not intended for doctoral students. However, I am sure that in the subjects in which she specialized in her thesis (chaos and relativity) she knows no less than physics professors who do not work in these subjects. And in general her specialization is in history, philosophy and the teaching of science, which is exactly what we need here on the site and not only here, to raise the profile of science. Besides, not all knowledge is acquired in academia.
A. Ben Nar, I'm sorry for entering into a debate that is not mine, and of course it is better for Gali to answer herself, but from what I see in the resume that you brought Gali did a doctorate in the history and philosophy of science in the years 1999-1994 and at the same time served as a lecturer or teaching assistant (it is very acceptable to teach during the second and third degree studies) . Later, as a PhD student, she taught courses at the Weizmann Institute and elsewhere. The courses at the Weizmann Institute are given to master's and master's degree students who study there. The course she taught was before I started my PhD there, but if I remember correctly a friend of mine who did the course praised it in my ears.
A. Ben Ner,
I found a serious error in your previous response (39):
R. H. Rafa. Yam is not "just rude"
R. H. Rafa. Yam is ** completely ignorant ** and rude.
to R.H. Rafa.im
You are not arrogant.
You are just rude.
Apart from that, I have an informative question for you:
Who are "Moshe and 'S'" that you covered in your last comment (No.-38)?
Of all the respondents to this article, no one identified with these names. Tel.
No wonder Dr. Weinstein does not answer your nonsense such as: "What qualifies a university graduate in the art of theater to teach physics at a university and private relations at the Weizmann Institute?"
Such a stupid question is suitable for those people who are studying for a bachelor's degree and think they already know everything.
Not only that, those arrogant people are also jealous of people who know a little more than them and who spent less time studying than them (the arrogant ones).
Now, who is the bigot who wants to answer that I am arrogant?
post Scriptum
Moshe and 'S'. Sit quietly until they address you. Maybe that way you will learn something.
to Arya Seter.
Your response (No.-35) is the embodiment of classical chivalry in all its glory. I have a feeling that you are of Polish origin,
just like me
And yet I wonder…
What qualifies a university graduate in theater arts to teach physics at the university and private relations at the Weizmann Institute?
Who and in what framework are private relations taught at the Weizmann Institute?
Gali, thanks for the interesting article.
I agree with those who claim that this was not a real mistake by Einstein, but perhaps an inability to anticipate technology 100 years back, but there is no need to expect that from him 🙂
In the physical aspect, I was very impressed by the experimental success of the American team. It seems to me that the head of the group is a former Israeli who studied in Israel, and to me it is a shame that it is difficult to find a place for such talented experimenters in the Israeli universities.
If I understand correctly, this is a method that has already been tried, but this is the first time that such a level of accuracy has been achieved, and it is certainly impressive.
A. Ben Ner - Gali specifically stated in comment 16 that there are indeed missing and unnecessary things in her resume and even took action to remove it, I assume with the intention of putting something updated soon. She did all this in response to your comments…
Dr. Gali Weinstein.
You have one more small will... (corrected version)
As far as I remember, special relativity is studied in the scientific faculties,
In the first year of the first degree, second semester, (maximum in the second year of the first degree).
At the Weizmann Institute of Science, as far as I know, they don't learn to describe first at all.
In what framework, then, is special relativity taught at the Weizmann Institute?
To Dr. Gali Weinstein.
You will have another small one...
As far as I remember, special relativity is studied in the scientific faculties,
In the first year of the first degree, second semester, (maximum in the second year of the first degree).
At the Weizmann Institute of Science, as far as I know, they generally learn to describe first.
In what framework, then, is special relativity taught at the Weizmann Institute?
To Dr. Gali Weinstein. Thank you for your answer.
But why did the resume disappear?
The photo of Einstein with the girl is from here - a rare film of Einstein shot in color:
http://corporate.gettyimages.com/marketing/m02/einstein_landing/index.asp?movie=large
And that's the explanation for the movie. Filmed at: Princeton University
Dated: May 16th, 1943
This footage was discovered in the home movie library of Leo Mattersdorf, who was an accountant and personal friend of Einstein. The clip itself is from an annual event hosted by Einstein at his home in Princeton. It shows the great scientist in an informal setting, having fun and relaxing.
As far as I know, the girl's identity is unknown.
Your question is over...
Why was Dr. Gali Weinstein's resume deleted from her website:
http://www.notes.co.il/gali/index.asp
Right after I posted it here in my comments #14, 17, and 18 below?
In its place you can now see a heartwarming photo of Albert Einstein with a lovely girl.
Who is the cute girl?
Just carrying Einstein's name in vain.
The most he said is equivalent to someone in the 15th century for example saying that he did not believe that supersonic flight would be possible.
This is not a theoretical impossibility, but an incidental saying of Einstein's (at most) which is a technological prediction - when everyone knows that such a prediction is not serious.
It's a shame, Dr. Weinstein, that you didn't bring things up more critically and get carried away (of course) after the far-fetched titles of one scientific journal after another (no matter what its "respectability").
sympathetic:
Thanks. Do you know how this relates to the heat equation?
Being is 'Brownian motion' and consciousness tries to find 'order' in it.
You're right.
I just wanted to throw in a comment that it is legitimate in some cases to perform an experiment on a gas to get valid results for a liquid, certainly in the case of statistical physics principles. In short, I wanted to strengthen Dr. Weinstein.
Nimrod:
My reaction came out too quick, in the heat of the moment, and I regret it.
Society:
It seems to me that everyone here knows what is different and what is common between liquid and gas and there is no need to make it the topic of discussion.
I raised the issue only to protect the name of Einstein that people like to stand on his shoulders to look great.
All I tried to do was reduce the validity of Einstein's statement and make it clear that he was not talking about some physical principle here, but about a point difficulty at a certain time, with the measuring devices of that time and with the materials you worked with (as opposed to a fundamental and permanent impossibility).
It is legitimate for the discussion to drift following such a comment towards the accumulation situations, but I think it is unnecessary for a debate to develop here between people who actually agree with each other.
Nimrod:
I knew I was opening Pandora's box 🙂
1. Did I claim that liquid and gas are the same thing? No. I said that "it makes sense to talk about them as "the same thing". There is point in talking. And I even put "the same thing" in brackets.
2. Did I say that 100 degrees Celsius at atmospheric pressure is the critical temperature of water? No. I wrote that it is a point on the coexistence curve of two phases. This is the point where a straight line of constant pressure intersects the curve. I wrote what you wrote about phase transition exactly in relation to this point.
3. I have no idea what table you are talking about (from which, according to you, I deduced something), but let's say. The diagram is a form of abstraction of physical processes that actually exist in the universe. The trip in the diagram, as you defined it, describes a real physical process, where there is a continuous transition between something that most of us would subjectively recognize as a liquid, and something that most of us would recognize as a gas.
In this case *no* (not emphasized!!!) phase transitions take place.
Like many others here you sinned by not reading the comment you responded to.
Amichai
In answer to your question: "Where does the square root of the number of seconds in a random walk come from?" I will try to explain the things in the article in a slightly different way and relate it to a random move. If we wanted to write the equations of motion of a Brownian particle according to Newton's laws F=m*a, we would encounter a problem since the acceleration is the derivative of the velocity with respect to time. In Brownian motion the speed is not a continuous function and therefore not a shear. The way to deal with this problem is not to write the equation of motion for a single particle but to look at a collection of identical particles (ensemble), it turns out that the distribution of a collection of Brownian particles has a diffusion equation in which the second derivative instead of twice the diffusion constant is equal to the first derivative at the time of the distribution from this it can be understood that The width of the distribution in a random walk goes like time - or the characteristic distance from the origin changes like the root of time. It can also be learned from the units of the diffusion constant that the diffusion constant is given in units of length squared divided by time
(to relate the members in the diffusion equation).
By the way, if I'm not mistaken, the great thing about Einstein's article from 1905 (the year of the miracle) is his ability to estimate the size of the liquid molecules from the random movement of the particle floating in them. In doing so, Einstein showed that molecules and atoms are not only theoretical objects, but he proved their existence (without being able to directly observe them at the time).
jewel,
Liquid and gas do not have identical properties, it is not for nothing that they are called different states of aggregation.
Fluid mechanics and gas dynamics are really not the same thing.
At atmospheric pressure at 100 degrees Celsius this is not really the critical point, it is an area from which the investment of additional energy will cause a phase transition, a transition of the critical point leads to reaching the state of supercritical fluid which is a state between liquid and gas where the properties of the material are between liquid and gas.
In any case, if you are talking about transitions in "normal" areas, then there are large changes in the physical properties of the material, the fact that we "travel" on the diagram as you mentioned does not mean that the physical properties are similar, transitions between different phases cause non-linear changes in the properties, I don't really understand How did you come to the conclusion that if liquid and gas are in the same table then they can be treated similarly.
I don't understand why people want to dig into someone else's report
This is not the place for an interview here, it seems nosy and petty
Does the doctor still teach any elective course at Haifa University?
I will thank you and I will not be ashamed. I also went and looked for your resume on the Internet when I saw the first article.
In my opinion, the main reason for all the criticism directed towards you is your past. Although your articles are dozens of times clearer than the articles of a certain Dr. here in the field of exact sciences, they find reasons to disparage your writing apparently because you are not a "scientist" and therefore "who are you to study this material with us, graduates of bachelor's degrees in mathematics, economics, etc."
Therefore, there is no need for you to respond to the articles, unless something burns inside you to explain them, you probably don't get paid for comments, while the detractors will get to know you and appreciate you over time.
By the way, no. Ben Ner - As someone who is familiar with the track in geophysics at Tel Aviv University, I know that their track overlaps in most of the main courses with the track of physics graduates.
A note regarding the gas-liquid issue:
In atmospheric extraction it is indeed possible to distinguish between 2 states of water accumulation - liquid and gas. This is because at a pressure of 1 atm there is a point on the coexistence curve between liquid and gas at 100 degrees Celsius, which is actually the point that allows us to detect a phase transition from liquid to gas (there is a discontinuity in the entropy, and an investment of capsule heat that does not raise the temperature but only evaporates the the liquid).
But if we look at liquid and gas without the limitation of a constant atmospheric pressure, then it is possible to start with a liquid (for example), and gradually increase the temperature and pressure in such a way as to bypass the critical point, and then gradually lower the pressure and temperature, until we find ourselves in a situation that most of us would define as a gas, but actually we will not be able to point to any specific point during this process and say "here, here we went from liquid to gas", the transition will be completely continuous.
Therefore, it makes sense to talk about liquid and gas as the "same thing" (Fluid in English, it turns out that in Hebrew it is called "flowing"), and it makes sense to draw a parallel between liquid and gas.
Explanation of a critical point:
http://en.wikipedia.org/wiki/Critical_temperature
http://www.notes.co.il/gali/index.asp
To Dr. Gali Weinstein
The information that appears in my response (No. 14) below, was copied from your website.
Except for reducing the spaces between the lines...I didn't touch it.
And to the point
In my humble opinion, it would have been better to emphasize the scientific innovation in the article and not try to present it in a way that is in my opinion
Sensational, using the name Einstein who can sell anything.
No. son. candle. You publish my resume as if you are already starting to gossip about me. It's really stupid to post my resume here. What's more, my CV that is published on the Internet - and it doesn't matter where you pull it from - and even if I put it on the Internet - is not a scientific document.
Apparently the Weizmann Institute thought I was the genius of the generation and that's why he accepted me to teach relativity, didn't he? What do you think?… 🙂
No that doesn't make sense. It doesn't make sense that the Weizmann Institute would think I'm the genius of the generation and accept me to teach relativity. And so the logical explanation is that something is simply missing in the resume you posted above - something is probably not written there in the list you provided above. And it seems that there is also one or two unnecessary things.
For Amichai, here is the answer under the head of the chapter "History":
http://en.wikipedia.org/wiki/Brownian_motion#History
Start reading in the sentence:
Specifically, Einstein predicted that Brownian motion
....
To the rest of the respondents. Air is a gas by definition. When I gave the example of Archimedes' law it has nothing to do with the experiment discussed here. Rather, it is intended to give an example - such as fluid dynamics - for areas where one model is used to describe something else.
And for our purposes. Einstein himself knew that his formulation was only valid above a certain length scale. At the smallest distances even the Brownian particles should behave in the manner just demonstrated. But Einstein believed it would be practically impossible to track this motion. and why? Because of the very short time scales on which the Brownian fluctuations occur. For example, a silica sphere with a diameter of 1 µm immersed in water has a velocity that changes in both direction and size every 100 nanoseconds, and this requires a detector system with a response time of less than about ten nanoseconds. See the sources I gave above. The researchers now from Houston got around the problem by studying particles in the air. The investigation of the particles in the air is designed to circumvent the problem.
In fact, perhaps the essence of the discovery is the following. And I was afraid to put it in lest they tell me, "You put in too many technical terms", like they told me with the article about the photon and NOON modes a few sections above.... 🙂 So I put it on my blog and not here so as not to startle the readers….
But in fact the thing that is perhaps the most important (!) from a technical and physical point of view (beyond the ho-ha we beat Einstein...:) we won...) in the discovery is the following: the average instantaneous speed was found to be very close to the one calculated using the principle of equal distribution. The equal distribution principle means that in thermal equilibrium, the average kinetic energy of the ½kT particle - the energy it has for its movement - is determined only by its temperature and not by its size or mass - this principle is one of the basic pillars of statistical mechanics. The experiment proved that a silica glass bead has the same average kinetic energy as a single air molecule. Raisen's study is the first direct test of the equal distribution principle for Brownian particles. And read the abstract in Science and those who have access to the entire article can read that the researchers want to cool the beads and move on... this is what Raizen says:
"We've now observed the instantaneous velocity of a Brownian particle," says Raizen. "In some sense, we're closing a door on this problem in physics. But we are actually opening a much larger door for future tests of the equipartition theorem at the quantum level.”
There, he expects that equipartition theory will break down, leading to new problems and solutions surrounding the quantum mechanics of small particles composed of many atoms.
That is, in the sacred language... they dealt with the "classic" principle of equal distribution. Close the door. Now they are turning to the quantum realm. They expect that the principle will be violated and then there will be new problems...
And Einstein, who was afraid of God playing dice (and Niels Bohr who told him: don't tell God what to do) didn't think that a hundred years later there would be so many problems...
To all those interested. Below is the summary of Dr. Gali Weinstein's resume. Quoted from the Internet.
With all the respect and appreciation that I have for Dr. Weinstein, and I do, the puzzlement arises, how does one get a bachelor's degree in theater arts - Tel Aviv University. Did Dr. Weinstein come to teach physics at the Hebrew University of Jerusalem in 1994-9 and special relativity at the Weizmann Institute in 2001-2?
Name: Gali Weinstein Grenk
Specialization: Science teaching, inventive thinking in science and technology, science in communication
Education:
Change degree
1985-1988 BA Theater Arts, Tel Aviv University
1988-1993 MA History and Philosophy of Science, Univ
Tel Aviv (master's thesis on the history of chaos physics)
At the same time studies in the geophysics department.
1994-1999 Ph.D History and Philosophy of Science, Hebrew University
(PhD thesis on Einstein and the path to relativity)
2008-2009 Informatics and Librarianship, Haifa University
Teaching experience:
Course year and institution:
1994-1999 Physics, Hebrew University
1999-2003 Philosophy of Science, Hebrew University
2001-2002 Special Relativity, Weizmann Institute of Science
2004-2005 The Philosophy of Albert Einstein, University of Haifa
2008-2009 The History of Relativity, The Hebrew University
2010 February lecturing on Newton and Einstein at the Technion course - conversion of engineers and scientists
Industry veterans for science teaching, "Minister of Education" project in collaboration
Academy of Sciences.
Michael is absolutely right.
When referring to air under standard conditions, the reference is to a gaseous state of accumulation, given
It is true to liquefy air, but very low temperatures are necessary.
Archimedes' law of buoyancy does not refer only to liquids, but it is a law that characterizes any phenomenon of buoyancy, it refers to ships that float on the surface of the water, also to submarines under the surface of the sea, airships that float in the air, therefore the inclusion of Archimedes' law to air does not make it a liquid.
Another fix,
Buoyancy is not the lifting force as you wrote in the response above, the lifting force is different from the buoyancy force (although buoyancy can cause the lifting of a body such as a zeppelin).
Dr. Gali Weinstein
Where does the square root of the number of seconds in a random walk come from?
explanation please? Thanks.
By the way, of course when I said "particles floating in the liquid" I meant "particles". hovering in liquid".
Floating is a special state and of course the Brownian motion of what floats is much more limited than that of what floats.
Speaking of the activity of remote ghosts - one of the commenters here on the site is called a ghost and works remotely 🙂
jelly:
The modes of accumulation accepted in our places (beyond exotic modes such as plasma) are solid, liquid and gas.
Air is a gas and not a liquid.
The fact that there are laws that apply to both gas and liquid does not make the gas a liquid.
Regarding Einstein talking about particles floating in a liquid.
The air in the Earth's atmosphere is a liquid - a formless substance with mass and weight.
Let's take Archimedes' principle. The buoyancy effect - Archimedes realized that a body that is partially or completely submerged in a liquid exerts a lifting force equal to the weight of the liquid it displaces. Look also Jules Verne in Five Weeks in a Hot Air Balloon got it right? 🙂 Archimedes principle is valid for bodies floating or submerged in any liquid, including the air, water, or oil.
True, people always try to show that Einstein is wrong. A week ago I was at an event honoring the 2010 Wolf Prize in Physics recipients, Alan Espa, John Klauser and Anton Zillinger. Why did they receive the award? Because they showed that Einstein was not right when he told Max Born in 1947 that there is no possibility of ghosts acting at a distance... and they may even receive a Nobel Prize for it... in this case they were also, as you know, probably right :). But they all said that Einstein was their hero and Klauser added, when he received the book with the relativity manuscript as a gift: "I'll put it under my pillow"...
The following response was written before Ami's response (you I agree) and was delayed due to internet problems I encountered.
come on!
People feel more important when they say Einstein was wrong, right?
Einstein did not speak of a physical law that prevents the measurement of the particle's speed at any moment, but rather that with the tools at his disposal he was unable to do so, and his genius was expressed in the fact that he found a way to draw the correct conclusions even without measuring the quantities he could not measure.
Beyond that - he was talking about particles floating in a liquid and not about a particle carried in the air by means of a laser beam, so it turns out that even with the tools available to us today, we have not yet been able to perform the measurement he claimed he could not perform.
And regarding the static universe (crescent - response 1)?
He did not insist on anything!
Rather his formulas said that it was not static, but since he was not an astronomer, he believed what the astronomers said at the time regarding the static nature of the universe and therefore did not insist on the correctness of his original theory and changed it to fit the reality he was reported to have observed.
As soon as Hubble's observations showed that the universe is not static, he accepted the conclusion with joy and happiness.
Don't be too quick to conclude that Einstein was wrong. History has already shown more than once that precisely those who tried to disprove his opinion are the ones who were wrong. And for number 1: Einstein was not wrong, the equations of relativity showed a dynamic universe but not the observations. Only after Hubble showed in an observation that the universe is dynamic Einstein corrected his advice and called his assertion the biggest mistake of my life. And from everywhere today it becomes clear that there is also a place to state that he entered into the equations to balance a dynamic universe.
Dr. Weinstein, the article was translated in a clear language, thank you for the article.
If I didn't know what a drunk move is I wouldn't understand anything from this explanation.
I promised that this time I will write the article very accessible to the general reader...
That is, with a minimum of physics and a minimum of physical terms.
But for those who are more interested in the physical professional side, here are explanations that contain a little more physics in articles abroad:
http://www.sciencedaily.com/releases/2010/05/100520141206.htm
http://physicsworld.com/cws/article/news/42679
And here is a really popular explanation:
http://blogs.discovermagazine.com/80beats/2010/05/21/refuting-einstein-in-4-easy-steps-physicists-measure-brownian-motion/
I didn't understand but it sounds interesting
Einstein was also wrong more than once. (He insisted that the universe is static)