IV. Foam-well slides

Purpose of tool:

            These versatile well slides are made from Foamies, an inexpensive craft product that is non-toxic, non-absorptive, easy to cut, and quick to assemble.  When exposed to water, the adhesive backing on the foam sheet will not loosen from the plastic or glass surface to which it is attached.  These clear-bottom well slides may be used with either dissecting or compound microscopes, with or without the benefit of unbreakable coverslips over the wells. Wells may be made in all shapes, sizes, and depths.  The well slides are particularly useful for viewing small crustaceans (such as daphnids, amphipods, isopods, brine shrimp), small mollusks (snails), small insect larvae, and many other small organisms. Slides are unbreakable and easily cleaned.

Required materials:

Clear, heavy acetate transparency sheets for floor of well slides [Alternate floor materials: clear plastic lamination sheet, Plexiglass, Lexan clear polycarbonate sheet, or glass slide.]

Foam sheets made of EVA (ethylene vinyl acetate) that are available in many hobby/craft stores, or craft sections of discount stores. [Option #1: Darice Foamies white, sticky-back sheet. An on-line source is: ArtCity.com. Cat. # DRC-114413 specifies white Foamies 9 in x 12 in x 2 mm, 10 pack for $3.97. Sheets 6 mm thick are also available.][Option #2: KIDS Funky Foam Sticky Back EVA Sheet. Item #10506 at Hobby Lobby stores.]

Hand-held paper punch for making circular or oblong holes [Alternative: X-Acto knife with new blade for making custom-shaped wells.]

Marking pen

Scissors

Soft cloth or facial tissue

Assembly and use of this tool:

1. Use the pen to mark off 1 in by 3 in rectangles on the paper backing on a foam sheet. Cut out the rectangles with a scissors.

2. Mark the locations and size of the desired wells on the paper backing.

3. With paper backing still attached to the foam sheet, use the paper punch to punch two or three round holes in the sheet. [Alternatively, use an X-Acto blade to cut rectangular wells by making repeated vertical slicing motions of the blade that extend completely through the foam and into styrofoam backing or cardboard backing. Avoid cutting movements that shred the foam.]

4. Now, remove the paper backing and carefully lay the foam rectangle on the clear transparency sheet, aligning it along the straight edge of the sheet. Repeat steps 1-3 until several rows of foam rectangles are attached to the transparency sheet.

5. Then, turn the transparency sheet over so that the clear side faces up. Use a soft cloth or tissue to press down firmly on all surfaces of the transparent sheet so that it thoroughly adheres to the foam strip and all air bubbles under the sheet are forced out.

6. Use a plastic pipet (or stretch pipet, as shown in Figs. 7 and 8) to place the specimen into the well and to adjust fluid level in the well. If no cover slip is used, the water level should be about even with the top of the well. 

7. If a cover slip is desired, then add enough fluid so that the well is slightly over-filled, creating a convex meniscus. Then, cover the fluid-filled well with a small rectangular strip of clear transparency sheet. Press very gently on the cover slip and tilt the slide sideways to drain off excess water drops. The specimen is now ready for viewing.

8. CAUTION: Make sure that the microscope light source does not overheat organisms within the well.
9. After making observations, slide the cover slip off the well and use a pipet to flush organisms back into their original container.

10. Wells should be rinsed thoroughly in distilled water and air-dried.

[Total cost is less than 10 cents per well slide. Estimated assembly time is less than 5 min/unit.]

Figure 9.  Assembly steps for foam well slides.