Fun Science Projects for Kids

It is Absorbing

Baby's diapers contain a substance that creates a cool magic trick.
Baby's diapers contain a substance that creates a cool magic trick.
©2007 Publications International, Ltd.

What's one thing you should know about super-absorbing polymer? It is absorbing! What's another thing? It's used in diapers. Now, you can take this knowledge and perform a magic trick.

The chemical name for super-absorbing polymer is sodium polyacrylate. Its chemical structure allows it to absorb a lot of liquid.

Ask an adult to help with this activity. The super-absorbing polymer can cause drying and irritation of the eyes and inner nose, so wear goggles when you use this material. And although it may look like Nerds or Pop Rocks, don't put any of it in your mouth -- it can be harmful if swallowed.

What You'll Need:

  • Goggles
  • 2 clean, unused disposable diapers
  • Scissors
  • Dark sheet of paper
  • 2 foam cups
  • Graduated cylinder (or small measuring cup with milliliter marks)
  • Water

Step 1: Put on the goggles. Cut open the part of a clean diaper that absorbs the baby's urine.

Step 2: Gently run your fingers over the cotton surface. Powder and crystals will fall out -- catch them on the dark sheet of paper. This material is the super-absorbing polymer. Don't rub your fingers too roughly over the diaper surface -- you want to collect the crystals, not the cotton. Put the super-absorbing polymer crystals into the bottom of a foam cup.

Step 3: Measure 2 milliliters of water, and pour it into the cup. Keep doing this until the polymer doesn't hold any more water. Calculate the total amount of water that the super-absorbing polymer from one diaper holds.

Step 4: Now here's the cool part: Repeat steps 1 and 2; then gather your audience for your magic trick. Don't let them know you have anything in the cup. Take the amount of water that the super-absorbing polymer can hold (you calculated this in Step 3), and slowly pour it into the cup.

Step 5: Talk to your audience for a minute as the water is being absorbed. Then dramatically turn the cup upside down. To the amazement of all, no water will come out.

Ever wonder why there's a picture of a cow on your bottle of white glue? Keep reading fun science projects for kids to learn the answer.

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