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## Air

Author(s): Nancy Moreno, PhD, Barbara Tharp, MS, and Judith Dresden, MS.
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#### Let's Measure

Complete instructions for conducting activities in this slide set, including materials needed, setup instructions, student sheets (in English and in Spanish), answer keys and extensions, can be found in The Science of Air Teacher’s Guide, which is available free-of-charge at http://www.bioedonline.org/lessons-and-more/teacher-guides/air/

Procedure

1. Divide the students into six small groups. (If your students are very young, you may prefer to conduct the activity as a discovery lesson with the entire class.)

2. Have the Materials Manager from each group collect a measuring cup and a sealable plastic bag. Give three groups approximately 7 cups of white popcorn each. Give 1 bag of colored popcorn to each of the remaining three groups.

3. Project the “Let’s Measure” student sheet while you explain that each group with white popcorn will measure 5 cups of popcorn into its bag; the group with yellow popcorn will measure 4 cups; the group with red popcorn will measure 1/4 cup; and the group with green popcorn will place only one kernel in its bag.

4. When the students have finished measuring, ask one student from each group to empty the popcorn from the group’s bag into the large, clear plastic bag (which you will hold in a central location).

5. Shake the large plastic bag. Ask, What do you think I’m doing? Lead the students to understand that the popcorn is being mixed. Ask, Are the colors of popcorn arranged in a special way in the bag? Students should note that the colors are mixed randomly.

6. Have the students identify which color of popcorn is represented by the most kernels in the bag, by the second-most kernels and so on, until you mention the single kernel of green popcorn. Follow by asking students to name other kinds of mixtures (e.g., fruit salad, crayons of different colors in a container, etc.).

7. Explain that air also is a mixture, made up of different kinds of gases. The different colors of popcorn in the large bag are present in the same proportions as the different gases in air. (Some students already will know that oxygen and carbon dioxide are involved in breathing. If the class is not familiar with this information, point out that the gas we take out of air when we breathe in is known as oxygen, and the gas we release when we breathe out is carbon dioxide.) Ask students to guess which color of popcorn represents oxygen molecules (yellow) and carbon dioxide molecules (green) in air.

8. Finally, point out that air is mostly nitrogen, represented by the white popcorn. The red popcorn corresponds to argon, gases present in air, but not absorbed by the body during breathing.

### National Institute of Environmental Health Sciences, NIH

My Health My World: National Dissemination
Grant Number: 5R25ES009259
The Environment as a Context for Opportunities in Schools
Grant Number: 5R25ES010698, R25ES06932

### Houston Endowment Inc.

Foundations for the Future: Capitalizing on Technology to Promote Equity, Access and Quality in Elementary Science Education