Page 2 - Demo

Let The Project Begin%u2014PART 1 We are going to collect cheek cells%u2014Eukaryote cells, from your mouth, stain them, and put them under the microscope. Then we will do that again, but this time, we are going to mount the cells on a semipermanent slide, which you can keep for awhile to look at or show your friends. This type of slide will not last many years as the solution we use eventually breaks down the staining of the cell, making it less easy to see details. Step 1: Swab Mouth. Take a cotton bud and wipe it against your cheek inside your mouth. (Cotton buds are readily available in supermarkets and chemists). Get it quite wet with saliva covered cheek tissue by spinning the cotton bud as you stroke your cheek several times. Cheek cells are continuously being shed and replaced so the bud will wipe away a few dozen cells without harm. Step 2: Rub the swab onto a glass slide. Put a drop of water onto a slide with the pipette and rub the cotton bud into the water. The cotton bud may absorb some of the water, so put another drop or two of water onto the cotton bud where it meets the slide%u2014helping to wash some invisible cheek cells onto the glass. I used two swabs as I%u2019m going to prepare two slides: one stained Methylene Blue, the other%u2014Iodine. Step 3: Stain with Methylene Blue. Use the pipette and add a tiny drop of Methylene Blue to the water. Stir and mix lightly with the pipette. If you are using Iodine, do the same with another pipette. I think Methylene Blue gives a better result, more pleasing to look at than Iodine. Make sure there is enough water on the slide to cover the area of the coverglass and to ensure no air bubbles are left in the sample. Step 4: Place a cover slide onto the droplet. Avoid unwanted air under the slide making tiny bubbles form: you place the coverslip down, one edge on the slide, holding it lightly between your finger and thumb, and then you tilt it forward to 45 degrees over the sample. Let it go and it will drop down onto the water, pushing any air out to one side. Use a piece of kitchen towel offered to the edges to blot up the spilled water. COTTON BUD COTTON BUD Coverslip 17