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Preparing Microscope Slides.

On this page you will find several techniques for preparing microscope slides that can help towards a great science fair project.

• Wet Mount Slide.
• Simple Staining Technique
• Well Slide
• Smear Slide
• Squash Slide

Wet Mount Slide

Introduction

This is a very simple technique that can be used for anything from crystals to sections of plants.

Materials

Sample, water, tweezers, eyedropper,microscope slides and cover slip, paper towels.

Method

1. Use the eyedropper to place a drop of water in the center of the slide. 2. The tweezers are used to place the sample on to the surface of the water. 3. Place the cover slip vertically so that it rest on the slide and touches one side of the water drop. 4. Carefully lower the cover slip over the sample and water. Make sure there are no bubbles under the cover slip. 5. Any excess water can be removed with the paper towel. Take care not to remove too much water.

Simple Staining Techniques

Introduction

Sometimes it can be quite difficult to identify different parts of a specimen. Staining the specimen can help especially where the stain is specific to one part of the sample.

Materials

Stain (e.g. India ink), microscope slides prepared using the wet mount technique.

Method.

1. Start with a slide prepared using the wet mount technique. 2. Use an eyedropper to place a drop of stain next to the cover slip. 3. Place the tissue next to the opposite side of the cover slip. 4. The tissue draws water from under the cover slip that is then replaced by the stain. 5. Continue to draw water from under the cover slip until you can see stain on the tissue.

Each time you try a new stain or sample you will need to experiment with different concentrations of stains. Another variable is how long you need to leave the specimen in the stain before viewing the sample. Type of specimen and the stain both influence the speed at which the stain is absorbed.

Discussion

Well Slides

Introduction

Sometimes the sample you are interested in is already in water. A good example is a sample of pond or stream water full of microorganisms.

It’s possible to buy well slides from scientific suppliers but a cheaper option is to make your own.

Materials

Microscope slide, clear nail polish, tooth pick

Method

1. Place the microscope slide on a clean level surface. 2. Draw a 1 cm diameter circle on the slide with the nail polish. 3. A tooth pick or spent match can be used to transfer the nail polish. 4. Build the well with several layers of nail polish. Let the nail polish dry between layers. 5. When you put the sample in to the well cover it with a cover slip. This will protect the lense of the microscope.

Don’t make the diameter of the well to large as it will make it difficult to find the sample. Also, the well should not be too deep or you will find difficulty keeping the object in focus.

Discussion.

Smear Slides

Introduction

Smear slides are excellent for liquid samples like blood or slime.

 
Materials

Microscopes slides (two or more), cover slips, eyedropper, paper tissue.

Method.

1. Use the eyedropper to place a drop of sample on to the microscope slide. 2. Smear the sample by dragging the edge of a clean microscope slide across the sample to produce a thin layer. Try to avoid creating any bubbles. 3. Carefully cover the sample with a cover slip and avoid trapping any bubbles. 4. Use the tissue to mop up any excess liquid.

Discussion.

Squash Slide

Introduction

If you have a soft sample this can be a useful technique but you must take care not to damage the sample.

Material.

Microscope slide, cover slip, eyedropper, tweezers, lens tissue.

Method

1. Prepare a wet mount slide with the sample you are interested in. 2. Over the cover slip place a lens tissue. 3. Carefully press down on to the cover slip to gently squash the sample. Take care not to break the cover slip. 4. Remove any excess liquid using the tissue.

Discussion.

Using the smear technique and staining with a dilute iodine solution it’s possible to study bone marrow. Try obtaining bone marrow from bones of sheep, cattle or pigs. Are there any differences in the bone marrow? If you can obtain a sample of yellow and red bone marrow see if they look any different. Research why they might look different. Do they have different functions?

WARNING: After you finish make sure all of the surfaces and materials are cleaned thoroughly with household cleaner. Never eat uncooked meat. Wash your hands.