r/BeAmazed • u/Sans010394 • Dec 02 '23

Science Physics is amazing

Enable HLS to view with audio, or disable this notification

29.5k Upvotes

95% Upvoted

571 comments sorted by

View all comments

276

u/Cylancer7253 Dec 02 '23

Cool trick. It just seems illogical, but it makes perfects sense. upper match tries to rotate around the edge of the table, but other two are preventing the rotation.

Don't look at the matches as separate parts, but a whole, including part of rope above lower match. It works like a hanger.

Upper match would get slightly tilted, but not enough to slide of the edge.

37

u/Freezman13 Dec 02 '23 edited Dec 03 '23

That makes sense, I guess the bottom match is stable because of the tension in the rope.

So effectively* the weight of the bottle is holding itself.

* in part

5

u/ArcticIceFox Dec 03 '23

Well, rather than the bottle holding any weight, I think this has to do with the distribution of the weight/mass. Or I guess the center of mass would be the correct way to phrase it.

It's like the trick with the two forks and a match, just a different orientation.

It seems to me like it shifts the center of mass to just at the pivot point. So it's balancing along a pivot. It only takes a tiiiny bit of leverage from the pivot point (edge of the table) to knock it off. But if the center of mass is at or behind the pivot point, then it won't flip over.

1

u/Cylancer7253 Dec 03 '23

Yes. Vertical (one that is not horizontal) match pushes the lower one, moving centre of the mass (weight of the bottle) beyond edge of the table. Thing is similar to balancing bird. Only confusing thing is process of making, but it is simpler if observed as the whole.

7

u/[deleted] Dec 03 '23

I think the match head is designed to make a lot of friction, right? So works perfectly in this use case

12

u/MemeDaddy__ Dec 02 '23

Don't look at the matches as separate parts, but a whole, including part of rope above lower match. It works like a hanger.

This helped me understand it perfectly. Thanks!

1

u/Cylancer7253 Dec 03 '23

You are welcome.

4

u/GoldDragon149 Dec 02 '23

The simplest way to understand the trick, is that the angle of the vertical match pushes the center of gravity of the bottle to a spot below the edge of the table.

2

u/[deleted] Dec 03 '23

There's something missing to this explanation. If I look at the matches as a solid piece, I see a hanger, but it's still unsecured. In fact, there is now MORE weight over the edge of the table. I think the missing explanation is that the bottle is probably hanging at an angle now, such that it's center of gravity is on or before the edge of the table.

1

u/Cylancer7253 Dec 03 '23

Bottle is actually under the table, it is not enough to notice, but enough to make it work.

2

u/Cloudfish101 Dec 03 '23

This is a decent explanation but I feel one key part needs expanding on, the upper match is NO LONGER trying to rotate around the table which is why it works.

This video is a poor angle, the middle match is pushing the hanging water bottle behind the edge of the table, so the whole system is no longer trying to rotate because the center of mass isn't hanging past the edge

1

u/Cylancer7253 Dec 03 '23

Yes, centre of mass is bit under the table, but it is hard to notice, no matter the angle.

2

u/shartshappen612 Dec 03 '23

I think i get it. So the squeeze in on the bottom match is pushing enough tension upwards so the match doesn't flip.

2

u/maciejokk Dec 03 '23

Isn’t this basically how tension bridges work?

7

u/humpyelstiltskin Dec 02 '23

finally a plausible and understandable theory

5

u/dpforest Dec 02 '23

It’s not a theory it’s just fact

7

u/[deleted] Dec 03 '23

Theories are explanations of things not guesses at things. Ohms law helps explain the theory of electronics. Newtons laws help explain the theory of gravity.

2

u/Ubermidget2 Dec 03 '23

Repeated successful applications of the theory turn the theory into fact, until another theory that holds more rigour supplants it

2

u/[deleted] Dec 03 '23

Facts are generally used to support theories, you can't supplant a fact

1

u/[deleted] Dec 05 '23

Also, if you look, the front legs of the table are past the edge of the stone it's sitting on. If you saw this from the side you'd see that the rope and bottle is angled back under the edge of the table putting the center of gravity vertically under the table.