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Science - 5th Grade
Standard 1 Objective 2
Believe it or not, this activity uses diapers to help students observe physical change.
Diapers contain fluffy filler that absorbs some liquid, but a white crystal mixed with the filler does most of the job. That crystal is sodium polyacrylate, a product developed for use in astronaut diapers. It is now used not only in baby diapers and a variety of personal products, but in gardening as well. Potting soil containing these water-holding crystals can is available at many garden centers. It is also marketed as something to be injected under lawns in our drought-prone state in order to conserve water.
A physical change is seen as the crystals absorb water. They expand to many times their original size. If left to dry out over a period of time, they decrease in size. Because the crystals swell in water it is not be a good idea to rinse them down the sink.
Warning: Caution students not to rub their eyes, noses, or face while working on this activity. Sodium polyacrylate has the same effect on body fluids and may be harmful to the students.
1. Use Science Process and Thinking Skills
2. Manifest Scientific Attitudes and Interests
4. Communicate Effectively Using Science Language and Reasoning
6. Understand the Nature of Science
Invitation to Learn
As a class, list the physical properties of diapers in a group discussion. Physical properties may include size, shape, color, odor, or texture.
Show students a baking soda and vinegar reaction. One of the most common ways this is done is with a bottle or test tube containing a small amount of vinegar and a balloon containing baking soda stretched over the bottle opening. When the balloon is tipped up and the baking soda mixes with the vinegar, a gas is formed that plumps up the balloon. Students design investigations based on this idea. Questions may include: