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Japanese jam jar lids close on their own, as if by magic

By Oona McGee, SoraNews24

Just the other week, the words “jam lid” started trending on Twitter in Japan.

This was a bit of a strange topic to hit the news, but after checking it out, the reason why the humble jam lid was attracting attention became clear — Twitter user @ktzwcrrk had shared a video showing a jam lid turning and closing completely on its own, as if by magic.

Check out the bizarre video here.

The jam seen in the video is made by Aohata, one of the most popular brands in Japan. A lot of people had a jar stashed away in their cupboard so when the tweet went viral, they tried it out for themselves and were amazed to see that the lid moved on its own for them as well.

“What is this? Is the lid alive?”


“Omg this is amazing.”

“It’s like it’s being controlled by the power of the force!”

“Wow, I wonder what causes this?”

It’s not clear what causes the lid to move of its own volition, and Aohata is yet to answer any inquiries about it, leaving us in the dark as to whether it was specially designed to close autonomously or not.

▼ We tried it ourselves, and lo and behold, it worked for us too.

The lid really does close on its own, sometimes slowly and sometimes quickly, depending on…who knows, really? We just placed the lid on top of the jar, without twisting it whatsoever, and it turned and closed at different speeds every time. It felt as if there was a magnetic force at play, although obviously there are no magnets involved.

While it doesn’t seal the lid tight, it does seal it, because you can’t just lift the lid off after it turns on its own — you have to untwist it again to open it. If you do want to seal the lid tight, though, it requires very little force to do so, as the automatic turn does most of the work in closing it for you.

Some people have mentioned that the same phenomenon occurs with other brands that have similar jar structures, so it’s likely that science, not magic, is at play here. Either way, the low physical effort involved in closing the jar makes it a fantastic example of universal design, and one we hope other manufacturers will look into producing too.

Source: Twitter/@ktzwcrrk via Net Lab

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© SoraNews24

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Still need to use hands, so what's the magic in there?

-1 ( +1 / -2 )

Notice how vertical the threads in the top of the glass jar are. Gravity and that steep slope let the lid close itself. Of course one has to wonder how well this works when he top of the jar is sticky with jam after some use?

0 ( +1 / -1 )

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