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Voltar para Compreendendo Einstein: A Teoria Especial da Relatividade

Comentários e feedback de alunos de Compreendendo Einstein: A Teoria Especial da Relatividade da instituição Universidade de Stanford

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2,513 classificações
875 avaliações

Sobre o curso

In this course we will seek to “understand Einstein,” especially focusing on the special theory of relativity that Albert Einstein, as a twenty-six year old patent clerk, introduced in his “miracle year” of 1905. Our goal will be to go behind the myth-making and beyond the popularized presentations of relativity in order to gain a deeper understanding of both Einstein the person and the concepts, predictions, and strange paradoxes of his theory. Some of the questions we will address include: How did Einstein come up with his ideas? What was the nature of his genius? What is the meaning of relativity? What’s “special” about the special theory of relativity? Why did the theory initially seem to be dead on arrival? What does it mean to say that time is the “fourth dimension”? Can time actually run more slowly for one person than another, and the size of things change depending on their velocity? Is time travel possible, and if so, how? Why can’t things travel faster than the speed of light? Is it possible to travel to the center of the galaxy and return in one lifetime? Is there any evidence that definitively confirms the theory, or is it mainly speculation? Why didn’t Einstein win the Nobel Prize for the theory of relativity? About the instructor: Dr. Larry Lagerstrom is the Director of Academic Programs at Stanford University’s Center for Professional Development, which offers graduate certificates in subjects such as artificial intelligence, cyber security, data mining, nanotechnology, innovation, and management science. He holds degrees in physics, mathematics, and the history of science, has published a book and a TED Ed video on "Young Einstein: From the Doxerl Affair to the Miracle Year," and has had over 30,000 students worldwide enroll in his online course on the special theory of relativity (this course!)....

Melhores avaliações

BH
22 de Jun de 2017

This course is very comprehensive and well prepared material for understanding the Special Theory of Relativity. Larry (the instructor) is very expert and has broad knowledge in explaining the course.

SS
8 de Dez de 2019

Almost anyone can learn about the special theory of relativity from these lectures. I actually can't believe that I studied from a professor who teaches in the USA and in so simple way. I am grateful.

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801 — 825 de 869 Avaliações para o Compreendendo Einstein: A Teoria Especial da Relatividade

por Алексей О

16 de Dez de 2017

Awesome!

por Lotus T

7 de Jun de 2021

G​reat!

por Felix H M M

19 de Out de 2020

AWESOME

por Chloe W [

27 de Jun de 2021

Great!

por Vijay N

10 de Jun de 2020

Great

por Gourang C B

23 de Mar de 2019

goood

por Hrishi S

21 de Nov de 2017

great

por Lương Đ L

26 de Mai de 2021

good

por Danilo C

9 de Jul de 2020

Wow!

por SHAMPRANESH D

10 de Nov de 2018

Good

por Abhijeet G

31 de Out de 2016

Yo

por Charles C

16 de Set de 2021

R

por Kell B

11 de Mai de 2018

f

por Mustafa S

15 de Jul de 2017

A

por Roger D

21 de Mai de 2020

I’ve enjoyed this course, which I’ve been following during the UK’s Covid 19 lockdown. It’s kept me happily occupied and, thanks to Larry Lagestrom’s generally careful and enthusiastic exposition, I’ve finally got my head round the relativity of simultaneity and its role in explaining the ‘pole in the barn’ paradox - something I never quite managed when introduced to special relativity as a physic’s undergraduate more than 50 years ago. So, a big thank you to Prof Lagerstrom.

I’ve a few reservations. First, the treatment of Einstein’s second postulate seems to be needlessly confusing. Starting in week 3, and then repeatedly throughout the course, the lecturer maintains that, by the phrase ‘the constancy of light’, used to describe the second postulate, Einstein means that light is a wave, implying, drawing an analogy with, say, sound waves, the the existence of a ‘supporting’ transmission medium - the luminiferous ether. It’s then maintained that, somehow - I can’t follow the argument - Einstein combined this interpretation of the constancy of light with the principle of relativity to deduce that the velocity of light is constant for all observers. I’ve read the relevant bit of Einstein’s 1905 paper several times, and I just don’t think this is what Einstein is saying at all. What it actually says is: ‘Llght is always propagated through empty space with a definite velocity c, which is independent of the motion of the observer’. There’s no recourse to any sort of argument, instead, it’s simply stated as a fact - just what you’d expect for a postulate. From some of the posts in the discussion forum, it would appear I’m not the only one having difficulties with this issue.

My second reservation - following on from the first - is that there’s too much time and effort devoted to the Michelson-Morley experiment. There’s no ether, the experiment was doomed to failure and all that time and effort deriving expressions for possible phase shifts - using highly questionable assumptions about the speed of the local ‘ether wind’ - could have been better spent.

It’s a small point, but my last reservation is with the derivation of length contraction, which I found hard to follow. The alternative approach - using a light clock sending pulses longitudinally along a train - seems much more straightforward and follows on nicely from the transverse clock used to explain time dilation.

Where I think the course really scores is in the derivation of the Lorentz transforms and the use of space-time diagrams. If you can work your way past possible early confusions and press on to these key topics,; you'll be amply rewarded for your troubles.

Alongside the course I’ve read Larry Lagestrom’s book, ‘Young Einstein: From the Doxel Affair to the Miracle Year’. It’s a good read and is particularly good at explaining the content of all Einstein’s 1905 papers.

por Richard E

18 de Set de 2021

Lecture delivery: Very engaging, in general. I do appreciate the historical background material. Difficulty: Way too easy. The professor seems to assume that the audience is weak in Math & Physics. The prerequisites for the course should include at least elementary Mechanics and Vector Algebra. Near the end, one problem should have been presented in 3D [t, x, y, z] to reinforce that the the previous problems were based on holding 2 of the 3 space dimensions constant. Leaving the details of the vector algebra as an exercise for the student to verify is justified with a change in the prerequisites. There was way too much explanation of algebra manipulation. Much should have been left as an exercise to the student! The mass/energy issue with respect to the speed of light should have been presented. This was skipped and could have been presented in a general sense with accompanying Internet GR references for derivations (E.g. DrPhysicsA on YouTube.com). Problem sets should not be optional! These are good student reinforcement opportunities. A presentation which needs to be revisited IMO: "The Twin Paradox" part 3.

por John R

16 de Set de 2017

Excellent presentation, clearly explained in generic language some of the esoteric concepts of the Special Theory of Relativity. In my Physics IV class, fifty years ago, we called this "Science Fiction I." I enjoyed the course. Only downside, I would think that a University with the standing of Stanford would produce a presentation that would use digital graphics instead of a white board and dry erase marker. With the capabilities of computer programming, this course could be greatly enhanced in the audio/visual area.

por Bhushan J

9 de Ago de 2017

In my view the course was a great exposure to Special Theory of Relativity and superbly conducted by Prof. Lagerstrom. I think some more rigor could be brought into as 'optional modules' and in the optional problem sets. There are some places where explanation could be elaborated or made clearer further in my view. Nonetheless for anyone who wants to know something about Special Theory (and vet intellectual appetite further), I would recommend this is a good place to start. Thank you!

por Prasad S

13 de Jul de 2018

At first, it really seems to be very slow paced, but latter you realize that those initial concepts were so key to the analysis and concepts in during latter lectures. The professor seemed to be very dedicated, and taught everything from the ground-up; which was really a help and thus, there does not arises a moment when you seriously struggle about the topic being discussed. HATS OFF to the professor for teaching in such a simplistic and conceivable fashion.

por Ameya K

10 de Mai de 2021

Pros: Everything is explained very well, to the point that even middle schoolers should be able to get it. It makes a university topic seem easy, which is impressive.

Cons: The course is very very long, and often feels very repetitive. A lot of videos don't seem necessary, and could have been shortened to half their length. Also, Week 1 is completely skippable because it doesn't actually teach anything about SR, just about Einstein's life.

por Lior S

17 de Jan de 2017

This was a great course which is taught by a passionate and patient lecturer. The whole 8 weeks covers the first half of Einstein's famous paper in detail. The pace can be slow, but of course you can always speed up the videos. The mathematics is very approachable - school level algebra is all you need. The only other prerequisite is a basic understanding of light and electromagnetic waves.

por Kelly S

20 de Dez de 2020

Good content, but too much focus on Einstein himself and philosophy. Could do with a little bit more of the math side of things, but I'm biased in that regard as already having finished my bachelors in aeronautical engineering. Spent too much time going over the examples, but they were well constructed and yielded a lot of insight.

por Floris v d P

9 de Dez de 2016

A comprehensive introduction to the subject, somewhat spoiled by the unrelenting reiteration of the most basics concepts in the earlier parts of the course. A bit of a pity, since the lecturer is a fairly engaging speaker when he is not busy interrupting the flow of his argument with mind–numbing repetition.

por Deleted A

18 de Dez de 2017

The content is really good. The quality of the content is excellent. The instructor's pedagogical skills are excellent as well.

The only criticism I have is with the length of the videos. I feel they could be shortened. Other than that, one of the best introductory courses for Special Relativity.

por Mitchell D

12 de Out de 2020

I think very highly of the course, and the professor, with one quibble: The professor had some difficulty talking in full sentences, which I found frustrating and annoying. Nonetheless, I enjoyed the experience, and believe that my understanding of Einstein's theories is certainly improved.