How to Do the Disappearing Water Magic Trick

Low Angle View Of Cropped Hand Holding Empty Glass

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In this science magic trick, you cause some water that you have poured into a cup to magically vanish, as if into thin air. Interestingly, this is a science magic trick that is based on a scientific principle that you don’t tell spectators about, as opposed to being a demonstration of a scientific concept that appears to be a magic trick.

In this effect, you pour some water into a cup and when you turn the cup over, no water pours out.

The water has apparently vanished. This science magic trick is similar to an easy magic trick that I teach called “Cold as Ice.” The concept is similar, but the method is slightly different and the end result is that some water that’s poured into a cup turns into ice. You can learn “Cold as Ice” by clicking here.


A compound that is known as sodium polyacrylate, which you can purchase at a hardware store, gardening store or nursery, and is sold in a form known as “moisture-saving pellets.” You can also obtain sodium polyacrylate from a disposable baby diaper. Simply tear open a diaper and remove and collect the moisture holding material within. With a quantity of sodium polyacrylate in hand, you will be able to perform the trick.

The Science

Sodium polyacrylate acts like a sponge and absorbs moisture. When mixed with water, the compound actually turns into a solid gel. And once the sodium polyacrylate forms a gel, the water is no longer liquid and can’t pour out.

Technically, the particles in sodium polyacrylate have a property known as being hygroscopic, which means that they absorb and hold water. Of course, this property is the reason why the compound is used in baby diapers to absorb moisture and keep babies dry and comfortable.


Sodium Polyacrylate (see secret above for more information)
A cup that you can’t see through water
You'll also need a container, such as a glass or a pitcher, to hold and pour water into the cup.

Or, if you like, and if it's convenient, you can also use a nearby faucet.


Before you present the trick and with no one looking, pour approximately one tablespoon of sodium polyacrylate into the bottom of the cup. You will probably want to experiment before performing the trick to test the amount of the compound as well as the volume of liquid that you can pour into the cup and will still effectively "vanish."

Performing the Trick

1. Pour about a quarter cup of water into the cup. In a short time, the water will react with the compound and form a solid gel. At this point, you can just offer a bit of patter on how the "magic is working."

2. Simply turn the cup over and show that the water has apparently vanished.


  • Be sure not to show the inside of the cup before and after the trick.


This is a science-based magic trick, however, you can perform it as a straight magic trick. In fact, there's a trick that's based on a similar concept but you turn the water into ice. We call it "Cold As Ice" and you can learn the trick here. In this trick, we use a sponge to act as the absorbent. The sodium polyacrylate probably won't work with this trick because the ice would stick to the resulting gel.