Instructions

Cut out microscope plates. Cut out two roughly equal sized pieces of posterboard and cardstock. They can be any size and shape, but if you want to pay homage to Leeuwenhoek’s microscopes they should be about 6 X 3 cm, with a slight taper at one end.

Drill light path (Figure 1-2). Drill an approximately 1 mm (1/16 inch) hole in the posterboard and cardstock. It is best to drill both at once and to drill into something like wood or additional posterboard to give a clean hole. The hole should be 1.5 cm from each side and the top, and about 4.5 cm from the bottom.

(optional steps). If you want to make a little pocket between the posterboard and cardstock for your lens, you can drill a shallow depression on the inside face of the posterboard using a 7/32 bit. This is not necessary since the cardstock will bend around the lens, but it makes a cleaner finished product. Alternatively, you can use two pieces of posterboard, but if you do you need to drill this pocket or the lens will be too far from the surface to be used (the lens has a short working distance). It is also helpful to carefully shave off any protruding paper around the holes with a sharp razor blade as lose paper fibers can be magnified along with your specimen.

Create the lens. The lens will be a sphere of glass whose diameter dictates the magnification. Aim for a lens of about 2mm in diameter since this is big enough to work with and gives a decent magnification. There are two main steps to this (wear eye protection when melting glass):

Step 1, stretch some glass (Figure 1-3 & 1-4). Holding the pipette/tube at both ends, place the centre in the flame and hold it there until the glass melts and wobbles freely between your hands. It helps to roll it in the flame to equally expose all sides of the heated area. When the glass is soft, remove it from the flame and immediately pull the two ends apart to stretch the glass very thinly. How far you must pull depends on the thickness of your glass source. You are aiming for a glass tube of >0.5mm. Too thick and your lens tends to be teardrop shaped rather than spherical, too thin and you have to feed a tedious length of glass into the flame or the lens can break off during step 2.

Step 2, form the lens (Figure 1-5). Once the stretched glass has cooled sufficiently to handle, break it somewhere in the middle of the stretched portion. Position the flame horizontally, and slowly feed the stretched glass into the flame from above. Watch this step carefully. A small, white hot glass sphere will grow at the tip of the tube as you feed it into the flame. It is critical to keep this sphere in the flame and not to let it cool before it is done (or when you reintroduce it bubbles will form in it). Keep feeding the tube into the flame until the sphere is about 2 mm in size. A nice trick to help keep this motion constant and the sphere in the flame is to feed the stretched glass though the loop of a pair of scissors so that about 5 cm of glass extends from the loop. Then hold the scissors by the blade and twist slightly so there is mild tension on the glass. This will hold the end of the glass steady as you feed it into the flame. Once the sphere is the size you want, remove it from the flame, let it cool completely, and break the tube off about 0.5 cm from the sphere. This gives you a short handle, like a lollipop, so you can avoid touching the lens during later construction. This also ensures the light path will be perpendicular to the ‘wound’ inevitably caused by breaking the lens from the tube (see below).

Things to note: your sphere should be a sphere, and not a teardrop shape. If you get a teardrop your glass was likely not stretched sufficiently, so go back to step one and stretch a new one to be thinner. Also note that you can make several lenses from one stretched segment of glass: when one sphere is done snap it off and start again. If you want to work with a smaller lens, you may need to drill holes smaller than 1/16th. Not only can the lens actually fall through the hole otherwise, but you need the hole smaller than the lens to limit the visibility of your light source background and ensure proper contrast.

(optional step) (Figure 2-1). If you are going to measure the diameter of your lens to compare with the calculation of its power (see part 2 on the next page), do it now, before you assemble the microscope.

Assemble the microscope (Figures 1-6 and 1-7). Holding your sphere by its handle, place the sphere over the hole you drilled in the posterboard (in the pocket if you followed optional step 2a) with the handle laying flat on the inside surface of the posterboard. Set the cardstock on top so the lens and handle are sandwiched between the two layers. Hold the two layers firmly together with the holes and lens lined up, and staple it twice about 0.5 cm from either side of the hole.

Things to note: these lenses have very short working distances, so your samples has to be very close to the lens. This is why you use the thinner cardstock on one side, and it means your microscope works in one direction: you look through the posterboard side and place your sample on the cardstock side. When you staple, do so with the cardstock side up so the staple is less likely to get in the way of the sample.

Figure 1-7. Staple the two pieces of paper together with the lens between them, and your microscope is assembled.

Figure 1-8. Take a pea size piece of tacky putty and press it on the subject (a feather barb is shown). The subject should stick to the putty when you remove it from the surface.

Figure 1-9. Press the putty with subject attached to the cardstock (thin) side of the microscope with the subject laying over the lens.

Make your focus mechanism (Figure 1-8, 1-9 and 1-11). The biggest challenge to making a microscope from paper is how to focus your specimen. The solution is to take advantage of the simultaneously elastic and sticky properties of tacky putty (e.g., Elmer’s Tack Adhesive Putty: the kind used to stick posters on a wall) to both mount the specimen and pivot it in relation to the lens. Recently used chewing gum works as well if you can’t find putty. To illustrate how this works, we will use mounting the barb of a feather as an example, but later will also explain how to mount other kinds of samples.

To start, put your onion skin on a flat surface. Take a dab of putty about the size of a pea and press it over one edge of the barb, as illustrated. Pick the putty off the surface, and the barb will stick to the putty and project from it. Now stick the putty to the cardstock side of the microscope just below the hole (don’t get putty on your lens) so the barb is right over the hole. This will be your stage, focusing device, and your movement controls. To view the specimen, hold the microscope as close to your eye as is comfortable (realistically this means holding is sideways), looking from the posterboard side directly into a light source (any light bulb, or a bright sky – don’t look directly at the sun). To focus, place your thumb on the putty. Pushing the putty up towards the top of the microscope will cause the sample to pivot closer to the lens, pulling down will cause it to pivot away from the lens. Movement from side to side will position the sample over the lens as desired.

The same principle is used to mount other kinds of samples. To mount any dry, solid specimen place it on a surface and press the putty over it and attach it to the microscope as described (I like feather barbs, insect wings, or onion skin to see the microscope in action easily). To mount a wet specimen, place a glass coverslip on a surface and mount it as described. Then drop your sample onto the coverslip and hold the microscope horizontally with the coverslip side up (so your sample does not drip) and look from the bottom. Wet samples can also be mounted between two coverslips, although this take a bit of practice. For this I suggest diatoms since they are big and regularly shaped. Forams and radiolaria are also good, but not as easy to find in nature (for some sample images see Figures 1-12, 1-13 and 1-14).

Figure 1-12. Clockwise from lower left these are a vein of an insect wing, the hairs on the trailing edge of an insect wing, cells in an onion skin, and the spikes on the surface of a radiolarian skeleton.

Figure 1-13. A example of an image with a lower magnification lens of live cells in liquid on a cover glass. This is the hypermastigote parabasalian Trichonympha from the hindgut of the termite Zootermopsis angusticolis.

Figure 1-14. Comparison of the same Radiolarian skeleton with three different microscopes. At left is a commercial McArthur-Cooke field microscope set at 400X. In the centre is the same skeleton photographed with the same camera (a Canon Elph) and at the same scale (showing the power of this lens to be about 200X). On the right is the same sample again but photographed using the Canon G9 and a different microscope with a much higher power lens. Download Complete PDF