# Will a football (soccer) diffract? [duplicate]

This question already has an answer here:

Apparently all objects have wavelike properties, so, if we kick a football (soccer ball, if you must) through a pair of posts, does the ball in any sense diffract?

If this is ridiculous then let me know and I will delete the question.

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## marked as duplicate by Ben Crowell, ACuriousMind, Kyle Kanos, Brandon Enright, BMSOct 28 '14 at 5:20

I don't think it is ridiculous – Bernhard Mar 29 '13 at 21:21
Also related: physics.stackexchange.com/q/57390 – John Rennie Mar 30 '13 at 9:39
@JohnRennie: Although I don't think it's a duplicate of the marble question, they are parallel in the sense that both involve two separate reasons why we don't observe the quantum behavior: (1) decoherence, and (2) the smallness of Planck's constant. For the marble, you addressed #1, and I added an answer addressing #2. – Ben Crowell Mar 30 '13 at 15:36
– Ben Crowell Aug 12 '13 at 21:30

The most straightforward thing to do is to simply estimate the diffraction. For a ball with momentum $p$, being kicked through a pair of posts separated by a distance $d$, the angular spacing of the diffraction pattern, in radians, would be $\theta=\lambda/d=h/pd$. Putting in p=1 kg.m/s and d=1 m, we get $\theta\sim10^{-33}$ radians. This diffraction angle is too small to be detectable.