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This kit allows you to differentiate bacteria using the Gram staining method. It includes Hucker's crystal violet, safranin counterstain, Gram's iodine stain, ethyl alcohol, 12 plain microscope slides, 100 coverslips, a medicine dropper, non-latex gloves, and our own study guide.
Want to use this kit for a science fair project? See our experiment ideas below to get you started.
Test different types of bacteria, such as Gram-positive Bacillus cereus and Gram-negative Rhodospirillum rubrum and compare how the stains differ. (Or just order this bacteria culture comparison set.)
What is Gram staining? Hans Christian Gram, a Danish bacteriologist, discovered that bacteria could be divided into two different groups - one that retained a stain ("gram-positive") and one that didn't ("gram-negative"). His method for identifying these two groups became the first step in any bacterial identification process.
Gram's method of staining has several steps: a sample of bacteria is placed on a microscope slide, then is stained and "fixed" with iodine. The slide is then washed in a solvent to "decolorize" the first stain. Gram-positive cells will retain the stain even after being washed in the solvent, but the stain will be removed from the gram-negative cells. This is because the cell walls of gram-negative cells contain more lipids (fatty substances). The solvent dissolves the lipid layer, allowing the color to be drawn from the cell. The solvent causes the gram-positive cell wall to dehydrate, closing the pores and trapping the stain inside the cell. In the last step, the gram-negative cells are stained a different color, to contrast them from the gram-positive cells.
Science Fair Project Ideas:
Take amazing close-up pictures of the bacteria you see under your microscope! This 3.0 Megapixel Digital Camera is a great deal! It takes high-clarity images and is easy to use.
Watch the following video to see this product in action.