We'll perform a compaction test to observe the differences in compaction among several types of soils. First, sharpen one end of a 10-inch-long dowel with a pencil sharpener. Using a ruler, measure 1 inch from the point, and draw a ring around the dowel.

Measuring from the unsharpened end of the dowel, mark and number ten lines 1/2 inch apart.

Fasten a wide rubber band to the top of a wooden spool with tacks or staples.

Slip the unsharpened end of the dowel into the spool, and put the point of the dowel onto the surface of the soil. Push down on the spool, forcing the point of the dowel into the soil, up to the ring line.

The number at the top edge of the spool will indicate the relative compaction of the soil.

Try the gauge in other places (e.g., lawns, gardens, baseball infields, paths, hillsides).

This way, we can find out where the soil is most and the least compacted. We can also observe how the relative compaction of the soil compares with the number and kinds of plants growing nearby. Why do you think there is a correlation?