Apart from the fact that this experiment looks pretty mesmerizing, the bead chain experiment, for the keen observer also looks like a contradiction of a scientific truth.
As you will see, the bead will pull itself up first (defying gravity?) before it falls down.
You’ve probably seen this exact experiment doing the rounds in the Interwebs.
But it isn’t! It’s simply science in action.
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Today, we’re going to have a closer look at this experiment and see the many ways the internet collaborated to explain this magical chain fountain phenomenon.
physics experiment, gravity
How It All Started
It all started when Steve Mould in a 35-second video clip showed the “jumping” self-siphoning beads. No explanation was given why this phenomenon happens.
It could be the lack of explanation or Steve Mould’s look of confusion and animation (and that charismatic face doesn’t hurt either!). But this video got the people of the internet together to find out the physics behind the beads.
Here’s the original video.
The Internet Comes Together
After this video, many other big websites and publications made all different kinds of attempts to understand it.
First, let’s start with the BBC Earth’s Unplugged Slow motion feature to figure out what was going on with the chain.
Steve Mould explains that this happens because as the chain moves very quickly downwards as it falls, the part of the chain that is still in the glass is also pulled very quickly. And this part of the chain needs to change direction (i.e going upwards from inside of the glass and then downwards to fall).
Now the beads can’t just suddenly change its direction this way because it “would require infinite force. So instead it changes direction slowly over the course of the loop”. And that’s why the upward movement of the chain that we all find fascination is necessary.
Here’s the video:
But as is expected of the Internet, there were mixed emotions with this explanation. Just go and read the Youtube comments and that’s probably just as fascinating as the video with some people contradicting this explanation and giving other reasons [or for some getting even more confused]
And so the quest for the answer continues on…
Here are a couple of the many attempts to explain this:
So this got some attention in the subreddit Ask Science. The question was asked and the people of Reddit started working.
For this Reddit thread, user Silpion bought his very own chain bead and went to do the experiment. After many tries, including one that tested if doing it from a second floor affected the movement (“increase in leap height with increase in drop height”) as well as leaving the beads to fall from a plate (did exactly the same thing)
He came to this conclusion:
“In Videos 5 and 6 you can see the pile being pushed back by the exiting beads. There is some kind of back reaction! Is it a whipping effect from the beads being pulled off and bouncing off the pile? I did another run and took some high-speed photos to check: Figures 8-14: You can see in some of them that the exiting layer is pushing off of the next layer! I THINK THIS IS OUR EXPLANATION!”
Boing Boing Joins the Discussion
Boing Boing has an interesting discussion about this too with many of its members chiming in their theories and asking, even more, questions…
And then Mythbusters advises everybody to try this at home.
Cambridge University Comes To The Rescue
And here are some clever guys from Cambridge University with a very detailed and clear explanation of the bead chain experiment. This is so far the explanation that my little brain can easily grasp and understand.
If you are so inclined to know the science behind this phenomenon, I highly recommend watching this video.
What do you think? Do you agree with the smart people of Cambridge University? Or do you have a different take on this? Don’t forget to add a comment below!