A Waterdrop Microscope

We can make a microscope out of a drop of water. The one we will build here will be surprisingly powerful, capable of showing not only individual cells, but the nuclei inside the cells.

And we can make it in about a half an hour or less, from scraps found around the house.

Here's what you need:

  • Three spring-type clothespins
  • A stiff piece of plastic sheet
  • Some glue (I used hot-melt glue because it sets fast)
  • A block of wood
  • A flashlight or table lamp
  • A sheet of cardboard for a base
  • A small piece of aluminum foil, with as few wrinkles as possible
  • A glass slide (or another piece of the stiff plastic)

The Waterdrop Microscope

(Click on the picture to see a larger image)

Cut a piece out of the stiff plastic sheet. I used the plastic that almost everything is packaged in these days, the kind everyone hates because it is so hard to open the packages.

Using a paper punch, punch out a nice round hole in the plastic. The hole will be about a third of an inch wide, but the size is not critical. But it should be nice and round.

Glue the plastic to the end of one of the clothespins, so the hole hangs over the end, as you can see in the photographs.

Glue the clothespin down onto the block of wood.

I took another clothespin apart to make the slide holder, but that ended up being too high to allow the microscope to focus on the slide. You can fix this like I did, by wedging some paper under the spring, but using craft sticks would be a better solution (I didn't have any craft sticks handy).

Whatever you use, glue them to the block of wood now.

The waterdrop

Cut a small piece of aluminum foil to act as a mirror, and glue one edge of it onto the cardboard. When the glue is dry, lift the other end so the mirror is at an angle, so the light is reflected up onto the slide.

Place a drop of water in the hole you punched in the plastic. Take apart another clothespin, and use it as a wedge in the jaws of the first clothespin. This will be our focusing wedge. We slide it in to lower the drop towards the slide, and pull it out to raise the drop.

Arrange a flashlight or table lamp so that the light reflects off the aluminum foil mirror and up through the slide and into the water drop.

Now put your eye very close to the water drop, and focus it until you can see a clear image of what is on the slide.

What you see will depend on what you have on the slide, but when I put a slide of the mouthparts of a bee onto the slide holders, this is what I saw:

Bee mouthparts

When I looked at a slide of some onion skin stained with methylene blue dye (which stains DNA dark blue) I could not only see the cells, but I could see the dark spot in the center that is the nucleus:

Onion skin

It was very difficult to get the camera to focus on the slide, and not other parts of the microscope, so the photo is not the best I have ever taken. Using your eye, the cells are in crisp focus.