A video of a ladder moving by itself was going viral on Twitter.

Uploaded by Twitter User Weepinggg, it received more than 2,000 retweets since it was posted on March 23.

So my friend send me this video showing a ghost ladder caught on CCTV in terminal 4 construction site LOL some kind of paranormal activity pic.twitter.com/RPBaTe5GO8

— •ᴥ• (@weepinggg) March 23, 2017

Before you call Ghostbusters to investigate this "sighting", you might actually want to slow down and realise that this video is just a false alarm.

Firstly, it's most probably not taken at Changi Airport and not at Terminal 4's construction site. The original video was filmed somewhere else and uploaded to YouTube, and another channel claims it was filmed in Indonesia.

In fact, it had gone viral on Reddit last year on the thread r/videos, with the source for the video coming from yet another site.

We can't confirm the location of where it was filmed, but we can, however, offer an explanation as to why the ladder was moving by its own.

It's physics, man. 

Turns out, this isn't the first time a ladder walked by itself, as it has happened time and time before.

Let science help you understand what's going on.

Firstly, many of these ladders were situated on a downward slope.

It may not be an obvious or steep incline downwards, but it does allow for gravity and weight to work together.

Then, a rocking motion to make the ladders "walk" begin with a gentle nudge.

Not convinced? Look towards traditional toys, and you'll start to understand this a little more.

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This movement is termed passive dynamic walking, a cheem scientific term for the action that causes the toy and the ladder to "walk".

Their movements are as a result of a slope inclined at an angle that is gentle enough for the object to keep rocking due to the forces acting on the object, but not so much that it tips over and tumbles away.

Therefore, you have nothing to fear now that science has explained those freaky movements.

Until the lights are off, that is.

TL;DR :

Top image via Alex Trambolino's YouTube video

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