Dismiss Notice
Join Physics Forums Today!

Solving Rubik's Cube

  1. May 18, 2012 #1
    Can solving Rubik's Cube be learned?
    I see people solving the cube in under 30 seconds.You think these people have some inborn talent in spatial rotation recognition that only geniuses possess.
    If someone were to give me a cube that had to be solved in 24 hours to receive a million dollar prize, I don't think I could do it.
    With so many different starting positions it seems like it can't be taught to the average person.
    You either have the ability or you don't.
  2. jcsd
  3. May 18, 2012 #2
    Long time ago SciAm ran a piece about the application of group theory to Rubik's cube. They profiled some "cubemeisters" who used special well-oiled competition cubes to solve the puzzle very fast. Don't know if the article's online or not. Didn't find it in a very cursory search, but you can probably do better.

    I did find an academic paper on group theory & RC.

    http://www.math.harvard.edu/~jjchen/docs/Group Theory and the Rubik's Cube.pdf

    (edit) Still couldn't find the original SciAm article, but if you check out the references on Wiki you'll find something. Bottom line, there are definitely theory-based algorithms to solve the cube. What people do is learn an algorithm then practice like crazy so they can operate quickly.

  4. May 18, 2012 #3
    I see 7 and 8 year old kids solving the Cube on You Tube. I am sure they know nothing of Group Theory.Who taught these kids? How did they learn?
    I also remember the Sci. Am. article in the early 1980s when the Cube was first popular.
  5. May 18, 2012 #4
    How about this? This video has 22 million views:

    Last edited by a moderator: Sep 25, 2014
  6. May 18, 2012 #5
    http://www.greatnecktools.com/upload/products_images/CP3.jpg [Broken]
    Last edited by a moderator: May 6, 2017
  7. May 18, 2012 #6
    These people just memorize an algorithm and develop muscle memory. To me, it's about as impressive as some child listing pi to the 500'th decimal. Sure, that neat, but not useful at all, and certainly no indication of intelligence.
  8. May 19, 2012 #7
    Its basically a rote memorization formula. You can find a solution formula in the booklet that comes with most rubiks cubes now a days. Its basic and easy. I got to the point where I could solve a cube in about two to three minutes, and that was using the long solution. There are apparently quicker solution methods. And I am certainly nothing near a genius.
  9. May 19, 2012 #8
    It is quite easy. Unless you want to break speed records, you have to memorize something like 4-5 sequences of 10-15 rotations each. You solve the cube by layers, first one face and the "rim" around it, then the middle band, and then the opposite layer with its rim. There are plenty of instructions on how to do that on the web.

    The masters memorize about 100 sequences and choose the most efficient ones depending on the configuration of the cube.

    The alternative is to use a heap of Lego pieces and your phone.

    Last edited by a moderator: Sep 25, 2014
  10. May 19, 2012 #9

    Jonathan Scott

    User Avatar
    Gold Member

    One can find little books or information on the internet which gives systematic rules for shuffling around two or three cubes without affecting others. These rules tend to involve several steps because of the need to undo side-effects on the other positions. When my kids (who were 14 and 10 at the time) found my old booklet on how to solve it, they memorised most of the steps within a day or so and can normally do the cube in two or three minutes.

    Experts use moves with fewer steps which take the side-effects into account but have a more complex effect. Again, they just learn to see the patterns and memorise the moves.

    Of course, the process of working out the moves in the first place is much more complicated. The basic principle is that simple moves have big side-effects, so moves that have a simple effect tend to involve several steps, typically preparing the required change, then performing it, then undoing the side-effects by reversing the preparation moves.
  11. May 19, 2012 #10
    I'm going on 29 years of never having solved a Rubik's Cube. I've also never done a backflip. Both, of course, can be learned. If they couldn't, no one could do it.
  12. May 19, 2012 #11

    I like Serena

    User Avatar
    Homework Helper

    I knew a guy who could solve it in 13 seconds.
    He was practicing and asked everyone to help him practice.

    I took a cube out and reversed it.
    After 5 seconds he found out and looked stupidly at me for about 5 seconds, since he couldn't believe I had done that. :biggrin:
    Then he popped a cube out, reversed it, and finished solving the cube.
    It still took him less than 20 seconds!

    To put things into perspective, he was studying computer science, but had to stop after a couple of years, since he couldn't complete the courses.
  13. May 19, 2012 #12
  14. May 19, 2012 #13
    It must be like a complicated game of tic tac toe. When you were a little kid you got all excited, playing many games. A little older, you found out the winning strategy and you lost interest in tic tac toe.
    With rhe Cube there are some algorithms to learn. The question becomes not how to solve it, but how fast can you solve it. Like a previous poster said, for record times a lot of muscle memory is involved.
  15. May 20, 2012 #14


    User Avatar
    Gold Member

    I'm with Jimmy, although my approach would involve explosives rather than a hammer.
    I bought a book about how to solve one. Using that book, it still takes me over 5 minutes. One guy in particular, who was in the same SF club with me 30 years ago, could whip up any kind of checkerboard or striped design within a minute. When they came out with "Rubic's Revenge", it took him a very short while to be able to solve it within a minute. It took him a bit longer to make patterns.
  16. May 20, 2012 #15
  17. May 20, 2012 #16
    I was really fascinated when Will Smith solved it in The Pursuit of Happiness, but after I saw a video on youtube explaining how to do it, and solving it myself in 3 minutes, I realized it has nothing to do with intelligence - just memorizing some algorithms
  18. May 21, 2012 #17
    The answer is, it depends on how you solve it. If you solve it with algorithms, virtually anyone can do it. It's just a series of instructions. Without algorithms, yes, intelligence is required.

    But keep in mind that algorithms are like general formulas; they are derived to make things more convenient. Thus, if you solve algorithms, BUT you made them yourself, that is also an indicator of intelligence.

    I can only solve two layers effortlessly without using algorithms. For the third layer, I will need to apply commutators and conjugators, which will require quite a bit of thought.
  19. May 21, 2012 #18
    Isn't that life though?
  20. May 23, 2012 #19
    Thecla, interesting that you mention 24 hours. The original Scientific American article appeared in the 80's and did not show any moves but discussed the cube in terms of groups and operators. It took me three days, no more than 8 hours a day, to discover operators that would swap edge cubes, rotate edge cubes, swap corner cubes, and rotate corner cubes without affecting any other subcubes. With this set of operations I was able to solve any cube in about 7 minutes. That is, it was possible to solve a cube in less that 24 hours.
    Obviously the kids were doing something different but it seemed that this was some innate ability that is lost with age. Lots of kids under 10 were able to solve these. It was not some kind of four sigma savant talent but some common 3D sensitivity. I had a striking demonstration of this. Many years later a 7 year old son of a friend saw a solved Rubik's cube (something he'd never even heard of) on a shelf, picked it up and proceeded out of curiosity to twist faces, perhaps 7 or 8 rotations, enough to totally scramble it for any adult. After a moment's thought he then reversed all the rotations back to the original state and put it back on the shelf and didn't act like it was anything special. This was a fairly bright kid but not some kind of prodigy. There are lots of Rubik/group articles on SciAm.com

Similar Discussions: Solving Rubik's Cube
  1. Time Cube (Replies: 3)

  2. Solving a rubik's cube (Replies: 43)

  3. Do you rubiks? (Replies: 34)

  4. Rubiks Cube (Replies: 6)