Thread: Pi is out! Tau is in!

1. Oh look something that is twice the number of something else. Maybe we should use that bigger number if we ever need to use two of the smaller number. GENIUS.

Seriously. So fucking what.

I don't really see the big deal with even caring. 360 = 2pi. So hard to remember. All it does is change the fractions you would use in an equation. It's still the same fucking answer. And if tau is so much easier to use how come people haven't been taught that in the past?

Personally, from the point of view of teaching kids, I think Pi is easier. You learn about circles and shit at an early age. If you want to keep going and learn more about maths you should already have an understanding of things already taught to you.
Why change what you have already been taught? Surely it's easier to teach something using things that you already know than to have to learn something new just to make it "easier".
What would have to happen to make it work? Start teaching kids about circles but instead of using pi use tau. But teaching kids about circles using tau would make it so much more difficult.

2. I don't really understand why one would be in and one would be out. They both seem useful.

3. Originally Posted by Spectral
I don't really understand why one would be in and one would be out. They both seem useful.
In Physics, we often dropped all constants (essentially defining c or h = 1), then put them back in later with unitary analysis.

It blew up my mind once, when a Professor worked a problem on the blackboard then said, "And that's the answer, to some factor of the speed of light."

Seems to me, its a disservice to teach something non-standard to beginners. Once you're more advanced and can mentally substitute tau=2*pi, go ahead.

4. Yeah, I remember my school's Physics teacher. There was the formula on the black board it had 10 in upper part (among other variables) and g in the lower part and he just went: "Well these two annihilate each other" and removed both 10 and g. Because g ~10 and in Physics one doesn't care about math precision.

5. Originally Posted by ag666
Because g ~10 and in Physics one doesn't care about math precision.
My question is - 10 what ?

10 grams doesn't cancel out 10 m/s/s ... nor even roughly cancel out 9.8m/s/s

6. I do not approve this message.

7. Originally Posted by belfpala
In Physics, we often dropped all constants (essentially defining c or h = 1), then put them back in later with unitary analysis.

It blew up my mind once, when a Professor worked a problem on the blackboard then said, "And that's the answer, to some factor of the speed of light."

Seems to me, its a disservice to teach something non-standard to beginners. Once you're more advanced and can mentally substitute tau=2*pi, go ahead.
I suppose that's conceptually useful, but it just seems confusing to me. I think I'm better at tracking new information than most folks, but it still just seems intuitive to me to teach both up front, then just use one during learning stages. Sort of a, "oh, by the way, I should mention that tau is also used, but don't worry about that too much for now, we'll come back to that later". I personally like having that sort of thing so that when it comes up later, I don't feel like, "why didn't anyone mention this to me?".

8. I know books still exists, but in the future stuff like this will be easier to change with more and more stuff going digital.

edit:
I said stuff 2 times, I have to point out that english is not my first language! haha

9. Originally Posted by schwarzkopf
The fundamental flaw in the guy's argument is that we don't create constants like π, e or what ever because they make formulas easy.

We make constants to represent fundamental properties, π is a fundamental property of a circle (C/D) and therefore is correct by definition.

Defining ππ or τ or a homer to equal 2π is just part of your working, however they are not fundamental properties of the circle and are therefore not of any interest in pure maths or physics.
What is more fundamental though, the diameter or the radius?

10. Originally Posted by schwarzkopf
My question is - 10 what ?

10 grams doesn't cancel out 10 m/s/s ... nor even roughly cancel out 9.8m/s/s
1 something in the upper part and 1 m/s/s in the lower part are still there for the sake of Units.
You do realize that when you do math - Units doesn't matter (granted all units are in same magnitude, plus you already know what are the resulting Units) - and then you solve Units - math is not used (you deal with variables and their units).

11. It's already been mentioned before, but Euler's Identity would get confusing if pi were switched to tau.

12. As others have said this will change nothing. You'll see (τ/2) as many times as you see 2π.

13. Originally Posted by schwarzkopf
My question is - 10 what ?

10 grams doesn't cancel out 10 m/s/s ... nor even roughly cancel out 9.8m/s/s
Sounds like an introduction, the "1 Newton is about the weight of a box of chocolate (100g)" handwaiving, useful to get a first impression of the unit, but not really more.

14. Originally Posted by ag666
1 something in the upper part and 1 m/s/s in the lower part are still there for the sake of Units.
You do realize that when you do math - Units doesn't matter (you already know what are the resulting Units) - and then you solve Units - math is not used.
I'm confused by this; could you elaborate? I only went up through Physical Chemistry (well, that was my most difficult math applying class anyway), but I feel like I was pretty much always taught to check and make sure that the units come up right in the end, as if they didn't, something was wrong somewhere. This is really long ago though, I might be misremembering order of operations.

---------- Post added 2012-11-10 at 10:27 AM ----------

Originally Posted by Duronar
As others have said this will change nothing. You'll see (τ/2) as many times as you see 2π.
Aesthetically, adding division is yuckier, or at least not as intuitive for my brain.

15. I find it easier to multiply than to divide, so I'll keep on using pi.

16. Originally Posted by Anakso
This does seem to make a lot more sense, but I wonder how long it will take them to actually change the way we're taught from 2pi to tau.
Will never happen in the U.S hell the only reason anyone here knows the metric system is because for some odd reason thats how we weigh our narcotics.

17. Originally Posted by Spectral
I'm confused by this; could you elaborate? I only went up through Physical Chemistry (well, that was my most difficult math applying class anyway), but I feel like I was pretty much always taught to check and make sure that the units come up right in the end, as if they didn't, something was wrong somewhere. This is really long ago though, I might be misremembering order of operations.[COLOR="red"]
Agree with you there. Dropping units in solving something is lazy, you don't save much time but risk making mistakes that you would easily avoid with them.

18. Originally Posted by ag666
1 something in the upper part and 1 m/s/s in the lower part are still there for the sake of Units.
You do realize that when you do math - Units doesn't matter (granted all units are in same magnitude, plus you already know what are the resulting Units) - and then you solve Units - math is not used (you deal with variables and their units).
I never really liked that approach. Although it sometimes got hairy, I learned my physics by solving problems almost entirely symbolically. No calculators were allowed on tests, but if you did it right you could use symmetry to kill about half the work.

19. Originally Posted by Spectral
I'm confused by this; could you elaborate? I only went up through Physical Chemistry (well, that was my most difficult math applying class anyway), but I feel like I was pretty much always taught to check and make sure that the units come up right in the end, as if they didn't, something was wrong somewhere. This is really long ago though, I might be misremembering order of operations.[COLOR="red"]
Simple example: Speed = distance / time. Speed = 100 (m)/14 (s) = 100/14 (m/s) = 7.1429 (m/s). Units and math are two separate entities. You can easily divide meters by seconds.
Now let's see: Speed == 10 (m) / 10 (s). But we need to get the distance in 100 seconds = 100(s) * 10(m) / 10(s). We can get rid of 10s = 100. We know the units - meters. If we do not know units - we can get them by doing this: s * m / s = m

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