A scientifically curious boy examining a piece of vegetation through his microscope.
PHOTO: MOTHER EARTH NEWS STAFF
The wing of a fly looks like something from a monster movie . . . while pieces of hair suddenly appear to be as big as pencils! A child's first peek through a microscope can be the beginning of a lifelong fascination with a world that we don't usually see. The magnifying devices are fun and educational, provide both "rainy day" and outdoor entertainment, and appeal to adults as well as to youngsters!
Unfortunately, microscopes cost money . . . and nowadays, many folks just can't spare much cash for non-necessities, no matter how worthwhile the items may be. Furthermore, store-bought microscopes are often too complicated for young children to set up and adjust. And, of course, most people wouldn't want to carry an expensive piece of optical equipment along to the woods or seashore!
Simple Tools and Materials
Well . . . here's some good news for all you eager entomologists and budding botanists! You can build your own for about 25¢ (or even for free)! Furthermore, the homemade instrument is small enough to fit in your pocket and powerful enough to make grains of salt look big as dice! If you'd like to know how to make a microscope, all you have to do is think small . . . then collect the following materials:
You'll need a scrap of soft wood about 2" wide, 3" long, and 1" (or so) thick . . . a strip of thin sheet metal ("tin can" metal will work, but something a little heavier would be better) . . . carpet tacks or heavy staples (the sort you drive into wood with a "gun") . . . a penlight bulb (the kind with a solid glass bump at the top) . . . and—if you want clips to hold a microscope slide in place—two pieces of thin, springy wire (piano wire, for example).
The penlight bulb is probably the only part you'll have to buy (that's where the 25¢ comes in). But, if you're lucky, you might even be able to locate a burned-out bulb . . . which will work just as well as a new one would and won't cost you anything!
For tools and equipment, you'll need a piece of medium-grit sandpaper . . . a tube of household cement (white glue—or even modeling clay—will do in a pinch) . .. a hammer or a staple gun . . . a drill and two bits (one 1/4" or larger and the other 11/64") .. . tinsnips for cutting the sheet metal (don't yield to the temptation to use —and ruin—your scissors) ... a saw (if your woodblock will need to be cut) ... and needle-nosed pliers with side-cutters.
To turn all of your raw materials into a pocket microscope, first cut the wood to size, if necessary. (Actually, the dimensions aren't critical, but a 2" X 3" block feels right and will fit in most coat pockets.) Next, drill a 1/4" (or larger) hole centered and at a point about 3/4" from one end of the wood. With that done, round the block's corners and sand its surface smooth.
Now, with the tinsnips, cut the piece of sheet metal to about 1/2" x 2 1/2", and drill a hole (11/64" in diameter) centered and about 1/4" from one end of the strip . . . using sandpaper (or a file) to remove any sharp edges.
The tricky part then follows: Use the sidecutters on the needle-nosed pliers to carefully cut the bump from the top of the penlight bulb: This will become your lens. You may have to break off some sharp edges, so it's a good idea when performing this task to wrap a towel loosely around the whole operation (hands and all) to guard against any flying glass chips. This precaution will also help you keep track of that little glass mound you're working to cut free. When you're finished, the lens should be in the form of a solid hemisphere.
The next step is to place a thin ring of cement around the perimeter of the hole in the sheet-metal strip, and—again carefully—put the lens in place with its round side up. (Be sure the glue covers only the edge of the lens.) When you're finished, set the assembly aside to dry.
Once the adhesive has set, tack or staple the metal strip to the wood . . . so that the lens (which should still be positioned round side up) is directly over the hole in the block. If you want to add slide clips, bend in the very ends of a pair of 2 1/2" wires. Tack one clip on each side of the metal strip . . . and that's all there is to making a pocket microscope.
How It Works
To use your little device, simply bend the metal strip up so that the end with the lens is about 1/4" above the surface of the wood. You can use prepared slides (available at most hobby shops), or make your own from clear cellophane tape (the foggy kind won't work). Just cut a piece of tape about 2" long, and stick it to whatever you want to study, folding the ends of the strips so they won't stick to your microscope's clips.
For openers, try looking at such things as grains of salt or sugar, insect wings, grass blades, feathers (small, downy ones are best), hairs, and pictures from newspapers. Just place the slide (homemade or otherwise) so that the object to be viewed is over the hole in the wood and directly under the lens. Hold the slide down securely, either with the wire clips or with more tape.
Now ... hold the microscope toward the light (daylight is best, but don't look directly at the sun!), then peek through the lens and focus the instrument by pressing your thumb gently against the metal strip until the magnified object is clear.
Fascinating, isn't it?