Discuss what would happen if all the dust mites in an in-service mattress were exterminated. NASA is very careful to clean dust particles off satellites and space probes before putting them into space. Explain why scientists take this precaution. Explain the comparison that will be used to study the development of the old growth forest. You can ask your students to contribute to the assessment rubric by determining how many facts students should find and determining criteria for a well-organized list.
Mineral dust is everywhere.
It comes from volcanoes, sandstorms, mining, building, and manufacturing operations. Cover a tabletop or lab area with newspaper. Have students put a few tablespoons of play sand in the middle of a piece of thin cotton cloth about 6 inches by 6 inches. Tell them to close the cloth loosely around the sand, and then hold the bag they made over a clean microscope slide and shake it for a few seconds. Students can now put the slide on a microscope stage and look at the dust that fell from the bag.