How to make a microscope slide

Wet mount

Use a wet mount for anything living, anything soft, and anything that is already a liquid.

• Put a small drop of water on a clean slide. For pond water, yogurt or honey, skip the water and use a drop of the sample itself.
• Add the specimen with a toothpick or forceps, touching it into the drop so it lets go.
• Lower a cover slip. Rest one edge on the slide beside the drop and let the slip fall slowly, which pushes air out ahead of it.
• Start at low power, find your specimen, then move up.

Dry mount

Hair, feathers, a fleck of newsprint, a thread of cloth, a scrap of leaf or an insect wing need no liquid at all. Place it on the slide, lower a cover slip over it and look.

Thick specimens rock under a flat cover slip. A concavity slide, with a shallow well ground into the glass, holds them still.

Add a stain for contrast

Most cells are nearly transparent, so a stain makes the parts show. Methylene blue colors nuclei, which makes cheek cells and onion skin easy to read.

Put a drop of stain at one edge of the cover slip and touch a scrap of paper towel to the opposite edge. The paper draws the stain under the slip and across the specimen.

Vital stains are made for living cells, so you can color a specimen while it is still moving.

Things worth a first look

• Onion skin, peeled thin from inside one layer, with a drop of methylene blue.
• Pond water, straight from the jar, as a wet mount.
• Yogurt, a tiny smear in water, for the bacteria that make it.
• Your own hair next to a pet's, as dry mounts side by side.

Related

• Genetics experiments you can do at home
• How to use immersion oil
• Lab safety equipment and how to use it
• Taking microscope photos with your phone