Introduction: Cardboard and Water Magic Trick

Amaze your friends with this easy magic trick.

Step 1: Materials

-pocket knife
-cardboard
-water
-cup (in my opinion a clear glass works the best).
 

Step 2: Cardboard

Cut the cardboard so it is a little bigger than the glass.

Step 3: Water

Fill the glass about 1/4 of the way full. Then place the cardboard on the top of the glass.

Step 4: Done!

To start out put your hand on the cardboard and slowly tilt the glass upside down so that all of the water is sitting on the cardboard. Then slowly and carefully remove your hand off the cardboard. the cardboard should stay on the glass! Any sudden movements will cause the cardboard's seal  to fail resulting in a mess full of water.

Comments

author
typogenerator (author)2013-02-21

I haven't seen the one where the water stays in the glass, but if you can't reproduce it, it may just be an upside down camera ;)

author

it's not!

author
joearrieta (author)2013-02-22

Dude careful with that knife or you'll hurt yourself, oh wait...never mind.

author

yeah that's right be careful bub!

author
sisar (author)2013-03-01

nasty cut you got there buddy!

author

yeah!

author
QJBillionare (author)2015-05-24

I'm going to freak out my grandma she gets scared from stuff like this

author
Jerryfrye (author)2013-02-17

This is also useful if you get bad service at a restaurant. Place your tip in a water glass. Put the cardboard on and turn it upside down. Then you can set that on your table and slide the cardboard out. That leaves an upside down glass of water that can't be moved without making a mess. Not that I would ever do that. :-)

waterglass.JPG
author
nerd7473 (author)Jerryfrye2013-12-22

LOL that is funny!

author
sisar (author)Jerryfrye2013-03-01

thank you for the idea :D

author
bajablue (author)Jerryfrye2013-02-17

Mean... but priceless! ;-D

author
santhosh.sagu (author)2013-02-25

Dude be careful with knife in the next instructable. I could see some marks on your thumb in this instructable. take care.

author
rjprod (author)2013-02-23

I sure it was easier to do the trick then to invert the camera...take the picture...then have to reverse all the background images!!

author
HelenaTroy (author)2013-02-18

reminds me of when I used to work in a pub, of a tirck they'd pull now and hten. Put a beer mat on top of the glass, invert it, put the plass down on the bar, then carefully slide out the mat - the beer stays in the inverted glass, with no way to rescue it - can't get anything under the glas without breaking the seal and letting the contents loose..

author
natsterrr (author)2013-02-17

I've seen a youtube clip where they remove the cardboard and the vacuum + water tension keeps the water in the glass! I haven't managed to succeed with that one yet, I'm not sure whether there is a secret trick to it or not...

author
faacuunndoo (author)2013-02-15

It's not magic it's physics! You should search and explain why this happens I don't know how to explain it in english but It's something about atmospherical presure.

author
the norm (author)faacuunndoo2013-02-17

Magic is just stuff science has not made boring yet.

"Yesterday's magic often becomes today's technology.
It is then taken for granted as the magic seeps away."

"Any sufficiently advanced technology is indistinguishable from magic."
― Arthur C. Clarke

Yes, it is magic. And, yes, it may be physics - but I don't believe in physics, so I'm not sure.

author
jcvillar (author)2013-02-17

I'm guessing the weight of the water is causing the cardboard to flex outward, thereby causing the pressure drop.

author
qewt (author)2013-02-17

neat!

author
DeathAwaitsU045 (author)2013-02-16

Uses a simple yet very breakable vaccum in the cup

About This Instructable

26,861views

87favorites

License:

More by sgfidlin:Portable Stop Motion StudioWeekend ProjectsHalloween Jack o' Lanterns
Add instructable to: