Мы тестируем новую версию сайта. Эта версия обновляться не будет. Приносим извинения за временные неудобства.
We are testing a new version of the site. This version will not be updated. We apologise for any temporary inconvenience.
Estamos probando una nueva versión del sitio. Esta versión no se actualizará. Rogamos disculpen las molestias.

Site statistics

35225 facts from 177 countries related to 1198 phenomena have been registered in Archive. 2834 of them were solved, another 11033 are under verification for compliance with one of the 322 versions.

0 facts have been added for last 24 hours.

Share your story

You are in "News" section

This section accumulates world news published in the media and concerning facts, phenomena and/or versions.

Incredible illusion: the helicopter takes off, but the blades do not move

Added	Sun, 01/11/2020
Источники	esoreiter.ru
Дата публикации	Sat, 31/10/2020
Версии	Stroboscopic effect

In the video presented, it seems that the helicopter blades do not move, but this is far from the case. It's all about the camera that captured this situation.

In reality, the objects in the video do not move smoothly, but we see a lot of consecutive images in which the objects are located at a different point each time. Our brain "thinks" that they just move smoothly across the screen.

In cinema, this phenomenon is called the "stroboscopic effect".

It's all about the frame rate at which the video is recorded. If the frame rate is equal to the frequency of one blade circumnavigation in a 360-degree circle, or it manages to be in the place of another blade, then it seems that the blades are frozen in place.