Sciencemadness Discussion Board

strange trick on the beach, help me figure this out

Ubya - 10-8-2018 at 12:46

Last year i saw on the beach a guy selling random crappy pendants, but the way he was selling them was cool, i tried to figure how he was doing this trick but i couldn't. This summer i saw this guy again, apparently there are many of them in this area, all of them perform this trick but i could't figure how they do it, and i couldn't even find anything useful on the web.

The trick works like this:
this guy has a small plastic table, on the table there are hundreds of different stones and pendants (rock, glass, plastic, resin, etc) all put together, he tells you that he is selling good luck pendants and not all of the hundreds on the table are going to work for you, every one has his personal stone and so he shows you how to find your own.
you start chosing a random pendant from the bunch, you keep it in your open hand, the guy wets it with water taken from a bucket next to him, he then wets a brush in a milky white solution (if you ask what it is he says that is "acrylic paint") and puts a few drops of it on the pendant and on your hand, if nothing happens that's not your lucky charm, so you try with another random stone, when you find the pendant "compatible with your chakra bla bla bla" the white solution on your hand will turn bright pink (like the color of basic fenolphtalein).
the intresting part is that a stone that turned the solution pink in my hand will not do the same if the test is done on another person, this is where "every one has his own lucky charm" thing comes from.

a few more details:
if you have sunscreen on your hands, the white solution will leave a yellow stain on your skin, but easy to wash off.
if you put "your pendant" on someone else's hand and repeat tge test but with your hand under his hand, the solution will turn pink anyway (this bugs me the most).

so, how does this work? what is the milky white solution that he calls "acrylic paint"? how could it be that the same stone on someone turns the solution pink but on someone else it does nothing?

i thought it could be ph, so i secretly covered one hand with a solution of baking soda and the other with vinegar, but it did nothing.

if i find one of these guys tomorrow i will post a video of the trick


[Edited on 10-8-2018 by Ubya]

elementcollector1 - 10-8-2018 at 13:08

I imagine only one or a few of the stones are coated with a chemical that reacts with the milky white substance to produce the pink substance. What that reaction is, though, I'm unsure - you already ruled out pH indicators, it seems.

CharlieA - 10-8-2018 at 16:18

I think one or more of the pendants/stones/etc. have been coated with a drop or two of a phenolphthalein (PP) solution, which will turn pink when the "acrylic paint", that is, a suspension of some insoluble hydroxide is applied to it. Getting the PP solution in various places is just slight of hand, I think.

Ubya - 10-8-2018 at 17:03

Quote: Originally posted by CharlieA  
I think one or more of the pendants/stones/etc. have been coated with a drop or two of a phenolphthalein (PP) solution, which will turn pink when the "acrylic paint", that is, a suspension of some insoluble hydroxide is applied to it. Getting the PP solution in various places is just slight of hand, I think.


the problem is that if the stone was coated with something it would react with the white solution indipendently to who is holding the piece, but this is not the case, the same stone could turn pink the solution on my hand and do nothing on yours

Doc B - 14-8-2018 at 02:46

Hahaha how many pendants have you bought trying to figure this out?

DrP - 14-8-2018 at 03:12

Quote: Originally posted by Ubya  
Quote: Originally posted by CharlieA  
I think one or more of the pendants/stones/etc. have been coated with a drop or two of a phenolphthalein (PP) solution, which will turn pink when the "acrylic paint", that is, a suspension of some insoluble hydroxide is applied to it. Getting the PP solution in various places is just slight of hand, I think.


the problem is that if the stone was coated with something it would react with the white solution indipendently to who is holding the piece, but this is not the case, the same stone could turn pink the solution on my hand and do nothing on yours


... but he wets the stone before putting the white solution on - so he could easily wet with water for the first 2 stones and then wet with very mild acid on the 3rd one making it look like that one was different. The same stone that was normal for someone else is now pink for you because he decided it was time to apply the acid or the indicator or whatever it is he is doing.

Ubya - 15-8-2018 at 12:59

Quote: Originally posted by DrP  
Quote: Originally posted by Ubya  
Quote: Originally posted by CharlieA  
I think one or more of the pendants/stones/etc. have been coated with a drop or two of a phenolphthalein (PP) solution, which will turn pink when the "acrylic paint", that is, a suspension of some insoluble hydroxide is applied to it. Getting the PP solution in various places is just slight of hand, I think.


the problem is that if the stone was coated with something it would react with the white solution indipendently to who is holding the piece, but this is not the case, the same stone could turn pink the solution on my hand and do nothing on yours


... but he wets the stone before putting the white solution on - so he could easily wet with water for the first 2 stones and then wet with very mild acid on the 3rd one making it look like that one was different. The same stone that was normal for someone else is now pink for you because he decided it was time to apply the acid or the indicator or whatever it is he is doing.


he uses the same bucket of water every time, and as i said i already tried coating my hands with acetic acid and sodium bicarbonate, and nothing happened

DrP - 16-8-2018 at 06:03

Quote: Originally posted by Ubya  

he uses the same bucket of water every time, and as i said i already tried coating my hands with acetic acid and sodium bicarbonate, and nothing happened



So what that he uses the same bucket? It's a trick - when he wets the stone it is water + indicator or whatever - it isn't just from the same bucket. Or he includes some powder wiped on his finger or something. It's slight of hand - a magic 'trick' - you are supposed to think it comes from the same bucket.

Regarding the acetic acid and sodium bicarbonate - why do you think this is even relevant? What indicator did you use? We don't know what HE is using so why should your random chemicals work?



[Edited on 16-8-2018 by DrP]

DrP - 16-8-2018 at 06:09

If you are lucky he might show you the flaming cardamom seed trick in a glass of water. Apparently that one goes down well and amazes punters. No idea how they do that one. ;-)

Ubya - 30-8-2018 at 13:12

here is the trick, on this woman the solution turned pink with this stone

foto1spiaggia-1.jpg - 3.1MB

foto2spiaggia-1.jpg - 3.3MB
now he tries the same stone on another person and the solution doesn't change to pink. same stone, same milky solution, same bucket of sea water.
foto3spiaggia-1.jpg - 3.6MB

foto4spiaggia-1.jpg - 3.2MB

so what is this?

Loptr - 31-8-2018 at 13:13

Maybe some of the people don't have sunscreen on their hands?

fusso - 1-9-2018 at 03:44

Quote: Originally posted by Loptr  
Maybe some of the people don't have sunscreen on their hands?
According to wiki, sunscreen can contain various chemicals ranging from acids to bases. Maybe these chemicals contributed to the pH variations on different hands?

[Edited on 01/09/18 by fusso]

Ubya - 1-9-2018 at 05:10

Quote: Originally posted by fusso  
Quote: Originally posted by Loptr  
Maybe some of the people don't have sunscreen on their hands?
According to wiki, sunscreen can contain various chemicals ranging from acids to bases. Maybe these chemicals contributed to the pH variations on different hands?

[Edited on 01/09/18 by fusso]


the reaction works with or without sunscreen, the only effect of sunscreen is that if after the trick you don't wash your hand it will leave a yellow tint where the milky solution was.

ps maybe this info is important, once the solution turned pink i didn't wash my hand to test if after it dried it would remain pink, it didn't, while drying on my hand it returned to a white residue