Then, the boys got to use some of our many water transfer pipettes to add water to the sodium polyacrylate crystals! Of course, everyone had to be able to see! So we dumped it into a larger bowl and added more water!
We finally found the saturation point. I think that comparing different brands of diapers of the same size to see which brand can hold the most amount of water would make a great science fair project! What a fun hands on activity! I need to get my hands on a disable diaper and do this with my son! Thanks for sharing this great idea. My boys will love this experiment. Love the creative thinking behind this experiment which allows children to investigate things in their environment.
I am new at reading your blog and love it. I have 3 boys and last week we tried your experiment with diapers. It was cool and they loved it. How fun! Wonderful Wonderful! Since sodium polyacrylate locks liquids in, they won't be able to get more than a few drops out. Diapers are serious science!! Water is H 2 O. This means that it is made up of two hydrogen atoms H and one oxygen atom O.
But the atoms in a water molecule are bonded together in such a way that one part of the molecule has a negative charge and the other part a positive charge. Because opposites attract, water molecules are very attracted to each other and to other molecules which have positive and negative charges. Sodium polyacrylate molecules are very long and curly. The sodium parts, represented by the green circles and chemical symbol Na, have a positive charge and dissolve in water. The long portion of the molecule, represented by the purple squiggle, has negative charges.
When water is added, these negative portions of the long molecule are attracted to the positive end of the water molecules. As more and more water molecules are attracted, the long molecule stretches and straightens. This exposes even more areas that are attracted to water. Diapers: The Inside Story. There is some pretty cool science going on in a diaper!
See how chemistry is used to help disposable diapers really soak it up! First, open up the diaper and lay it out flat on a tray. What to expect. What makes the gel? Get a dry diaper and try this to find out! This is the expected result. Sodium polyacrylate is a polymer, which means it is a large chain of molecules made up of many smaller units known as monomers. Superabsorbent polymers expand when they come into contact with liquids like water, because water is drawn into and held by the molecules of the polymer.
Therefore the sodium polyacrylate acts like an extremely powerful sponge! If you tried adding salt to the mixture, you might have noticed that the texture and volume of the gel mixture changed back to a liquid. This is because salt breaks the attraction between water and polymer chains. The added salt breaks into negative and positive ions, which are also attracted to the water molecules. Each salt ion attracts several water molecules to it, thereby pulling them away from the polymer.
Eventually enough water is pulled away so that the mixture goes from gel back to liquid. This activity brought to you in partnership with Science Buddies. Already a subscriber? Sign in. Thanks for reading Scientific American. Create your free account or Sign in to continue. See Subscription Options.
Go Paperless with Digital. Materials Adult helper Eight clear plastic cups A glass will also work, as long as it is clear. Two to three disposable diapers The number needed will vary slightly depending on size and brand. The chemical you'll be working with is perfectly safe, but this will help with cleanup. Use the permanent marker to label four of the cups. If you're using glass cups, write the labels on a piece of tape and stick the tape to the cup.
Label the cups as follows: cup 1—one eighth teaspoon, cup 2—one quarter teaspoon, cup 3—one half teaspoon, cup 4—one teaspoon.
Place two to three drops of food coloring in the four unlabeled cups. Use the measuring cup to pour one third cup of water into each cup. Use a spoon or stirrer to mix the coloring and water. Open a diaper on your work space. Have an adult help you use the scissors to cut through the inside lining of the diaper and remove the powdery, cottonlike stuffing material inside. Place the stuffing in your zip-top bag. Check the diaper for any leftover powder—either scoop this up with your hands or use your spoon or you can carefully pick up the diaper and shake the remaining powder into the zip-top bag.
Set the diaper aside. With all the stuffing inside the bag, carefully seal it and shake the bag for one to two minutes.
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