ElI5: why does a rotating wheel or propeller spinning at high speed look like its spinning the other way sometimes?
In: Other
That is usually seen on recorded images, and it is because the rotation rate of the blade, is different to the frame rate of the film. So each new image has the blade in a new position, often near the last recorded image, but rarely the same, so the image appears to show a slow, sometimes reversed rotation. When in fact it is moving a great distance between images.
**Please read this entire message**
—
Your submission has been removed for the following reason(s):
* ELI5 requires that you *search the ELI5 subreddit for your topic before posting*.
Users will often either find a thread that meets their needs or find that their question might qualify for an exception to rule 7.
Please see this [wiki entry](http://www.reddit.com/r/explainlikeimfive/wiki/how_to_search) for more details (Rule 7).
—
If you would like this removal reviewed, please read the [detailed rules](https://www.reddit.com/r/explainlikeimfive/wiki/detailed_rules) first. **If you believe this submission was removed erroneously**, please [use this form](https://old.reddit.com/message/compose?to=%2Fr%2Fexplainlikeimfive&subject=Please%20review%20my%20thread?&message=Link:%20https://www.reddit.com/r/explainlikeimfive/comments/j23o7l/-/%0A%0APlease%20answer%20the%20following%203%20questions:%0A%0A1.%20The%20concept%20I%20want%20explained:%0A%0A2.%20Link%20to%20the%20search%20you%20did%20to%20look%20for%20past%20posts%20on%20the%20ELI5%20subreddit:%0A%0A3.%20How%20is%20this%20post%20unique:) and we will review your submission.
Latest Answers