File talk:Circle radians tau.gif

This animated gif has a critical error that undermines its entire point. It incorrectly labels the remaining arc after 6 rads as being τ rads. τ rads is the entire circle. This error is in all three previously uploaded versions.

Galhalee (talk) 17:10, 19 December 2015 (UTC)[reply]

If you look at the colors, the animation is correct. tau rads is the (yellow) angle, not the (red) section of the circumference. This could be improved by moving the labels or choosing other colors.

Nevertheless, you have a valid point: The animation as a whole does not make much sense, IMO: It first puts the focus on visualizing a correspondence between an arc of the same length as the radius and an angle measuring 1 rad, which is correct, but not really important in this context. And then, the animation raises the (wrong) impression, as if integer multiples of this angle would make up a full circle, only to eventually find out that there's still a remainder left to be count in.

So, what is this animation trying to tell us in the first place?

If its intended point was to slice a full circle into some nice (integer) count of equal fractions, it fails. The factor must include pi (or tau).

Given that the animation mentions tau rather than (2)pi, perhaps it was trying to visualize something special about tau (or pi). If so, it failed as well. Yes, the angle of a full circle is 1 tau rads or 2 pi rads, but other than the slightly easier representation in factors of tau rather than pi, there's nothing special to show here at all.

So, basically, I don't see the purpose of this animation. It only shows what is already obvious even without animation, and adding a sophisticated animation around it, it may be even misleading as if there would be more (and non-obvious) about it that needs to be emphasized on in an animation to fully understand the concept.

--Matthiaspaul (talk) 12:15, 19 December 2015 (UTC)[reply]

@Matthiaspaul:

Yes the colors are consistent but the shrunken red arc is completely unlabeled. You can question the point of any illustration but I'm trying to find a way to improve this one. Isn't the real problem the sudden introduction of an undefined and unlabeled red arc? I don't think this would be nearly as confusing if all the red were simply removed from this frame.

If the remaining arc needs to be highlighted then I think it should be labeled on its own. I'm bothered enough by this to construct my own animation but I would like some more feedback first.

--(unsigned) 2015-12-19T18:56:39‎ Galhalee

Yes, adding an extra label, changing the color of that remainder (or even gradually shading the color as the arc becomes longer) would work.

However, before you invest more time into creating your own animation, what would be the actual purpose of this animation? IMO, even a fixed version of this animation would not transport anything new, so why do you think we actually need it and shouldn't just use a simpler, more to the point, non-animated illustration?

--Matthiaspaul (talk) 19:11, 19 December 2015 (UTC)[reply]

While I see the point that is being made, I also see the same thing is being done with the pi file.

What you are seeing with each frame is the addition. The first frame has 1 radian in red. The second frame has 2 radians stated, but marks in red the one added radian. This continues to the sixth radian (to third for pi), after which the remainder fraction of the circle in radians is added making τ rads (pi radians). John W. Nicholson (talk) 10:50, 31 January 2016 (UTC)[reply]