Origins: Earth is Born

Student Handout

The Hunt for Micrometeorites

It is difficult to imagine that Earth grew from many small bits of dust and debris that were formed long ago in stars. Although most of the solar system debris has settled, meteorites do still enter Earth's atmosphere. While most of the rock and metal objects entering Earth's atmosphere burn up due to friction between the debris and atmospheric gases, some surviving fragments fall to Earth. In this activity you will hunt for remnants of the early solar system—micrometeorites that are about 4.6 billion years old!

Procedure

1. To gather material from your collector, first carefully lift the collector by the corners so that it hangs in a "U" shape, keeping one end of the "U" slightly higher than the other.

2. Hold the filter at the low end of the collector so that the water sprayed on the sheet will flow down into the filter.

3. Carefully wash all particulate matter from the collector into the filter assembly. Squirt the sheet with the water from the sprayer, starting at the top of one side of the "U," and wash back and forth to the bottom. Then switch and wash the other side. Finally, squirt the bottom of the "U" from the high to the low end.

4. Carefully remove the filter from the coffee can and spread it out on the square piece of cardboard. Cut out and remove a 5 cm wide band from the center of the filter (cutting the wet filter on a piece of cardboard helps prevent the sheer paper from bunching up).

5. After the water has drained from the filter, spread a very thin film of diluted white glue in the middle of the four cardboard-mounted microscope slides. The glue will anchor any particulate that has collected on the filter. Each slide must be coated from side-to-side and to within a half inch of both ends.

6. Lift the wet filter band away from the cardboard and center it across the microscope slides, with the particulate matter facing up. Keeping the particulate matter face up, lay the filter over all the slides. Set the microscope slides and filter aside to dry.

7. After the glue dries, have your teacher cut the four slides apart. Peel the masking tape away from the slide ends to free them and store in a plastic bag the slides that contain the most particulate matter.

8. Once all teams have collected samples, you will be given your slides to examine under a microscope. Use a table lamp to light your slide from above. Draw a picture on your "Identifying Sky Dust" handout of what is on your slide, and describe each object. Then conduct research to identify as many of the particles as you can.