08 August, 1994
The following field projects are an important part of my Biology curriculum. They are easy to set-up, inexpensive, and most importantly, they always work!
1. Making topsoil. In the field, dig holes through the topsoil in various habitats, noting how the composition and thickness of the topsoil varies with respect the dominant species of plant. Topsoil consists of broken rock, humus, living organisms, and water. It provides physical support to the growing plants by anchoring
root systems and supplies nutrients to the growing plant. It is easy to make topsoil in the classroom using materials collected from the field. Try growing flowers or vegetables in your homemade topsoil
2 liters of small local rocks or pebbles
12 liters of leaf litter (leaves, small twigs and bark.
Large tub to mix the soil in
hammer, burlap bag, And safety goggles
Methods: Place the rocks in the burlap bag, put on safety glasses and smash the rocks with a hammer until all of the pieces are less than the size of a pea. Pour the rocks and rock dust into the tub. Add the leaf litter and mix thoroughly. Add enough water to completely soak the mixture. Let the water evaporate over several days and use the mixture as potting soil.
2. How porous is the soil at the bottom of a pond? Many students believe that a pond is similar to a swimming pool - the nonporous bottom of the pond prevents the leakage, and eventual drainage of the water from the pond. To disprove this notion, try the following experiment.
Pond, lake or stream
3 inch diameter piece of PVC pipe about 3 feet long
boat bilge pump (manual)
magic marker - indelible
Methods: Locate a pond, lake or stream. In a shallow area where the water is only about 2 feet deep, rest the pipe on the pond bottom. Make a mark on the pipe about 3 inches above the waterline. Hammer the pipe into the soil to the depth of the mark (a block of wood placed on top or the pipe may facilitate hammering. Note the time and draw the water out of the pipe using the bilge pump. Time how long it takes for the pipe to refill. Because there are no leaks in the pipe, the water must be percolating up though the soil in the bottom of the pond.
3. Insects are easy to trap in the field. The methods that I outline below are sure to snare a sizable harvest for identification and observation.
Method 1. "Sticky boards" are small pieces of plywood that are coated on one side with a strong adhesive. I purchase mine from a local exterminator, but I understand that they are available in hardware stores. Place or hang the boards in various habitats, and collect the boards the following day. Insect species will vary depending on the habitat in which they are collected.
Method 2. Baited pit-fall traps. Dig small depressions in the soil of the habitat you want to study. Place 8 inch aluminum pie tins in depressions so that the lip of the tin is at ground level. Bait the traps with sugar water and let them stand overnight. You might also try baiting the traps with various solutions to see what ingredients best attract insects.
4. Identifying pollen. This project works best in the late Spring and early Fall when pollen counts are the highest. Students are amazed to discover the complex structure of pollen as viewed through a microscope.
5 glass microscope slides per student.
Clear plastic tape (Scotch tape works fine)
Methods: Tear off a 4 inch piece of tape and make a loop with the adhesive side out. Stick one side of the tape to the microscope slide and place the slides in the habitat being studied. Collect the slides the following day and view the pollen grains with a high-power microscope.