Take a very small drop of yogurt with the toothpick and smear it for 2 to 3 seconds on the slide. Place a small drop of methylene blue solution on a microscope slide (optional). Wear gloves and do NOT allow children to handle methylene blue solution. Place a coverslip on top. Remove excess solution around the coverslip with a paper towel or tissue. View in the compound microscope at 4 x or 10 x initially, before moving to higher magnification. Bacteria will appear small even at the highest magnification.