Vanishing Water Experiment
Experiment
- Place a new (definitely unused) diaper on the black piece of paper. Use scissors to carefully cut along the center of the inside lining and then remove the cotton-like material. Shake the loose powder you find onto the paper.
- Put all the stuffing material into a clean, zipper-lock bag. Scoop up any of the white powder that may have fallen onto the paper and pour it into the bag with the stuffing. Blow a little air into the bag to make it puff up like a little pillow and seal it. Shake the bag for a few minutes to remove any powdery material from the stuffing. Notice how much (or actually, how little) powder falls to the bottom of the bag.
- Carefully remove the stuffing from the bag and pour the powder into the plastic cup.
- Pour a half-cup of water into the cup. Mix it with your finger (or a spoon if you have to) until the mixture thickens. Stirring is actually not required as the gel thickens quickly on its own.
Observe the gel that the powder and water create. Turn the cup upside-down and see how it has solidified. Take it out and play with it. It’s amazing stuff and totally safe!
Materials List
- A new, disposable baby diaper
- Zipper-lock bag
- Scissors
- A Cup
- Water
- Black piece of paper
- Adult supervision
How Does It Work?
The secret water-absorbing powder in a disposable diaper is a super absorbent polymer called sodium polyacrylate. A polymer is simply a long chain of repeating molecules. If the prefix “poly” means many, then a polymer is a large molecule made up of many smaller units, called monomers, which are joined together (think of a chain). Some polymers are made up of millions of monomers.
Super absorbent polymers expand tremendously when they come in contact with water because water molecules are drawn into and held by the molecules of the polymer. The polymer chains act like giant sponges. Some can soak up as much as 800 times their weight in water! That would be one wet baby!
The cotton-like fibers you removed from the diaper help to spread out both the polymer and the, uh, “water” so that baby doesn’t have to sit on a gooshy lump of water-filled gel. It’s easy to see that even a little bit of powder will hold a huge quantity of water, but it does have its limits. At some point, baby will certainly let you know that the gel is full and it’s time for new undies!
In spite of their usefulness, these diapers can be a problem. If you’ve ever observed a baby in diapers splashing in a wading pool, you know that even one diaper can absorb lots and lots of water. Most public pools won’t allow them to be worn in the water because huge globs of gooey gel can leak out and make a mess of the filter system. Also, some folks used to throw them away in toilets – definitely not a good idea unless you’re a plumber or know one. For the most part, however, these diapers are a great invention and make for drier, happier babies.
Take it Further!
Experiment
- Secretly place one blue scoop of Water Gel into one of the three styrofoam cups. Don’t forget which one has the powder!
- Line the three cups up and tell a friend you want to challenge them to a game of three cup monte. Add water to one of the two cups that does not have the Water Gel in it. Ask your friend to keep their eyes the cup with the water.
- Start to mix up the cups positioning. To make the end result even more amazing, move the cups slowly. Ask them to point to the cup that has the water in it. Unless they had their eyes closed, this should be obvious to them.
Tell them that was too easy and pour the water from that cup to the other empty cup (without the Water Gel). Ask them to keep their eyes on the cup with water again.
- Mix up the cups again moving a little faster this time, but keep it obvious where the water is. Ask them to point to the cup that has the water in it. This should still be easy to do.
Again tell them how amazing they are. This time, pour the water into the cup that has been hiding the Water Gel. Tell your friend this is the last time.
- Move the cups around and have them keep their eyes on the one with water. When you finally stop and they point to the cup that should have the water, turn it upside down to reveal the water has vanished. Stack that cup inside one of the two other cups, inside the final cup. Turn the stack over to show that none of the cups have the water and take a bow! Your friend will think you are magical.
- Once you solidify water, take the gel and place it into a zip-lock bag and smoosh it with your fingers. Add a sprinkle or two of salt, shake the bag, and watch what happens. Salt wrecks the gel’s water-holding abilities. When you’re finished, rinse the salt water goo down the drain.
- Grab a new diaper and hold it over a large pan or sink. Slowly pour about 1/4-cup of warm tap water into the center of the diaper. Add more water slowly, a little at a time, until the diaper will hold no more. Keep track of how much water the diaper can absorb before it begins to leak. You may be surprised!
Want to share these amazing Jelly Marbles with your friends? place a couple in one of the included plastic vials and hand them out so your friends can enjoy their magical properties too!
Materials List
- Water Gel
- 3 styrofoam cups
- Blue scoop
- Water
- Adult supervision
Additional Information
Believe it or not, this amazing super absorbent polymer is reusable! That’s right, just let it sit out and the water will evaporate making the powder shrink down to its original form. To help speed this process along, it’s always best to spread it out as much as possible. A cookie sheet works really well.
After it dehydrates, add it to water again and make it solidify!
Science Fair Connection
Making water vanish is pretty cool, but it isn’t a science fair project. You can create a science fair project by identifying a variable, or something that changes, in the Vanishing Water experiment. Let’s take a look at some of the variable options that might work:
- Try using different liquids. Can the Water Gel solidify orange juice or coffee? Which liquid works the best?
- Compare different diapers. Which diaper has the most super absorbent polymer? Which of those solidifies water the quickest?
- The brand of diaper is the variable in this experiment. However, be sure to use the same size of diaper even though you are using different brands. For example, if you test a large, toddler-sized Pampers diaper against a newborn-sized Huggies diaper, your results will not be reliable. Everything needs to stay the same except for the brand of diaper, even the kind and temperature of water you use. You’ll find out very quickly if you get what you pay for or if there really isn’t much of a difference between the brands.
That’s just a couple of ideas, but you aren’t limited to those! Try coming up with different ideas of variables and give them a try. Remember, you can only change one thing at a time. If you are testing different liquids, make sure that the other factors are remaining the same!
