The Pond Viewer

Build a Pond Viewer so you can immediately see microorganisms and other material in a sample of pond water. It can be made from wood scraps, Plexiglas, rubber tubing, nuts and bolts.

Sizes can vary. The one illustrated here is 9" x 12". You will need two pieces of Plexiglas (cut at many hardware stores) at least 2" larger in each dimension that the viewing area you want. Select pieces of wood that are at least 3/8" x 3/4" to minimize splitting. You will need two pieces for each vertical side and two for the bottom of the Viewer, since the wood makes a partial frame on the outside of each piece of Plexiglas.

The top of your Viewer stays open for scooping water. The whole thing is assembled like a sandwich. The sides and bottom are sealed using a continuous length of 1/2" diameter plastic tubing between the two pieces of Plexiglas. Drill the wooden pieces and the Plexiglas and run small bolts through those holes. Three to five washers (depending on how flexible the tubing is) should be used between the Plexiglas pieces so the bolts can be tightened evenly.

Creating the sandwich is not difficult, but here are a few useful notes:

• Plan to drill holes so that the outside edges of your wooden pieces are about 1/2" inside the edge of the Plexiglas. This will make for a tighter fit.
• To avoid cracking the Plexiglas, first drill very small diameter holes, then drill the size you need for your bolts.
• When you tighten the nuts (or wing nuts), work around the Viewer, tightening each nut a little bit, then go 'round again to get even pressure on the plastic tubing.

When you have completed this window-like apparatus, attach a string at the top corner bolts to allow you and your students to take samples at various depths. You could bolt a thermometer to the Viewer as well. Your Viewer will provide many opportunities for observation, drawing, discussion and other forms of data collection. Plan to look at the water in the Viewer, and also remove the water samples for observation using microscopes and hand lenses.