Science Fair Tip: Microscope Slides

Science fairs… they can be a blessing and a curse. It’s the perfect opportunity to get students engaged, but projects can be daunting for students, parents and teachers alike. We’ve got you covered. We’ll be posting ideas and tips here, on Facebook and on Twitter to get you thinking.

Here is a pretty simple way to make slides if a student is interested in minute subjects like insects. All the materials are probably in your lab, with a few added from your toiletries cabinet!

Making a microscope slide simply means taking something you want to observe microscopically and placing it on a rectangular piece of glass or clear plastic. However, there are parameters for what to choose: The material must be thin and clear enough so light easily passes through it.

There are two types of basic slides—wet mount and dry mount—discussed in this article. The material and/or what you want to observe in that material determines the type slide to use.

We have you covered with instructions on both types and Carolina’s products that help in slide making and viewing. Experiment with many different materials. See what works best for your project.

Note: A razor blade may be required for thinly slicing certain wet and dry mount materials. Adult supervision is required for this activity.

Image courtesy Igor Siwanowicz, Max Planck Institute of Neurobiology/Nikon Small World, via National Geographic.

Wet mount

Materials (basic)

• Slides
• Coverslips
• Toothpicks
• Water
• Clear Nail Polish
• Scissors
• Forceps (optional)
• Razor Blade
• Microscope

Materials for wet mount viewing

• Cheek Cells (scrape)
• Tooth Plaque (scrape)
• Fruit or Bread Mold (scrape)
• Dust
• Soil
• Dry Food (such as coffee grounds, spices, or salt and sugar crystals)
• Fabric or Threads
• Plant Material
• Cork or Foam (thin slices—no coverslip needed)
• Other Appropriate Items Transferrable by Toothpick or Forceps

Procedure

1. Place a small drop of water or clear nail polish on a clean slide. Note: Using a mountant keeps the coverslip in place and prevents the material from moving or changing. When looking at living material or for a temporary slide, water is typically the mountant. If the subject material is liquid (such as pond water, paint, soapy water) or liquid food (such as yogurt or honey), there is no need to add a drop of water. Just place a drop of the liquid material on the slide.
2. Use a toothpick or forceps to gather non-liquid subject material.
3. Transfer materials to the water or polish drop by touching the toothpick or forceps to the mountant. If necessary, gently move the toothpick or forceps to dislodge materials.
4. Carefully lower a coverslip onto the slide.
5. Examine the slide under low and high power of the microscope.
6. Record your observations: write a journal entry, or draw or photograph them.
7. A slide made with nail polish is semi-permanent, if left intact. For a temporary slide, separate, then wash and dry the slide and coverslip. They are ready for reuse.

Carolina offers useful kits including all materials needed to prepare slides. The Oral Bacteria Kit (item #319346) provides all materials and detailed instructions for making permanent stained-oral-smear mounts. For making many basic slides, the Carolina™ Microscopic Discovery Kit (item #319316) offers all necessary supplies plus several sample materials, including pollen, insects, pond organisms, dust, hair, and garden soil.

Dry mount

As the name implies, this type slide doesn’t require any liquid for preparation. It is also easily made.

Materials (basic)

• Slides
• Coverslips
• Toothpicks
• Forceps (optional)
• Clear Nail Polish (optional)
• Scissors
• Razor Blade
• Microscope

Materials for dry mount viewing

• Feather
• Hair
• Small Insect or Insect Body Part
• Newspaper or Magazine (cut to size)
• Cloth (cut to size)
• Plant Matter (such as leaf, seed, bark)
• Other Appropriate Items Transferrable by Toothpick or Forceps

Procedure

1. Use a toothpick or forceps to gather the dry subject material.
2. Place the material on the slide.
3. Carefully lower a coverslip onto the slide. You may want to use a concavity slide to hold the specimen. NOTE: If you wish, make the slide semi-permanent by adding a drop of clear fingernail polish to the dry material before placing the coverslip.
4. Examine the slide under low and high power of the microscope.
5. Record your observations: write a journal entry, or draw or photograph them.
6. For a temporary slide, separate, then wash and dry the slide and coverslip. They are ready for reuse.

Making microscope slides is fun and exciting!

The mysterious microscopic world unfolding under the objective is a wonderful discovery for young scientists. After this activity, all your students interested in using microscope slides in their science projects are ready to get started on this fascinating adventure. (Now your only problem is helping find science projects for the rest of your class!)

You can separately purchase all the materials for making microscope slides. However, the Deluxe Slide-Making Set (item #319740) provides everything you need, including 72 microscope slides, 50 coverslips, slide labels, 7.5 mL of mountant, coverslips, forceps, dissecting needle, razor blades, and bibulous paper.

Carolina’s Microscope Slides Department also offers hundreds of prepared slides showing everything from basic household materials to botany specimens and histology specimens. Our staff will happily assist you in finding the exact slides to meet your needs. For more about slide making or locating a specific type slide, call 800.227.1150 and ask for the Microscope Slides Department, or visit www.carolina.com.