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. Ask them to draw the mineral dust as it appears under the lens of the microscope. They should look for any particles that are geometrically shaped and try to identify them with a crystal identification book. Then they can speculate about where the sand might have come from.
Arachnids Have students research arachnids.
For each type of arachnid students find, have them draw a picture and label it with the common name and scientific classification. They might begin with the tiny dust mite. In the past few years, scientists have learned how to observe the inner structures of biofilms or mucilages, which are built and populated by plain, humble bacteria such as E. Coli and salmonella. New findings about the genetics and biochemistry of biofilms are reported. A Primer An interesting and informative site about diverse, small arthropods commonly known as dust mites.