By Zach CoteGrade 10
Limestone Community School
The experiment that we have practiced was staining bacteria with different types of dye to get a final view of it under a compound microscope. The purpose of this experiment was to practice staining, to look at the bacteria up close under a compound microscope, and so we can learn how it’s done and how you go at doing this. When we performed this experiment, we thought that we would grow bacteria, stain it, and observe it under a compound microscope. Our hypothesis was that we would stain the bacteria cells completely and be able to see the bacteria up close and be able to see a lot of detail to the bacteria. To do this experiment, we used a compound microscope, water, grams iodine, safranin, a flaming loop, Bunsen burner, methanol, crystal violet, forceps, a Petri plate, swab stick, incubator and test tubes. To prepare for this experiment, we first had to swab an area of our choice and put it on the Petri plate. We then put the Petri plate in an incubator for 24 hours to set. The next day, we made test tubes by putting bacteria from the Petri plate into broth with our flaming loop and put it back in the incubator for 24 hours. To prepare a slide, you first place a loop full of distilled water in the center of the slide, then spread the drop into a thin film. After that, flame the loop before setting it down. You then take the slide and pass it quickly through the flame from the Bunsen burner three times, with the smear side up. This is called heat-fixing. After you pass it through a few times, add methanol to the slide and let it set for one minute. Once you do that, just wash it off with water and you are all done preparing it for the experiment.
To do the actual procedure, you first start with the slide that has a smear. You then cover the smear with crystal violet and let it set on the smear for 20 seconds. After that, rinse off all extra violet with water. You then want to cover the smear with grams iodine and let that set for one minute and after your time is up, you will rinse off all extra grams iodine. Once you have washed off the iodine, you will want to decolorize the smear with methanol but rinse off quickly after decolorizing. Then, you take a drop of safranin and let it set for one minute. The last step is to just rinse off the safranin and look at it under your compound microscope.
The data for our lab was right in the lab room. All of the supplies was given to us to use. We used the microscope to look at the different things and when we could see them we drew them. There were no calculations that needed to be done for our lab. The only thing that we needed to know was how much of the stains to use and how long they had to set.
In conclusion, the data meant that were able to dye the bacteria and be able to see it under a microscope all in the biology room. All the data for our experiment was provided in the biology room and the tools to work with them.
There was no sources of error in our lab. If there was one such as we didn’t have enough dye or we didn’t let them set long enough, then that could be a common error. If this error was to happen, you could ask for help by your teacher for the right amount to use, simply measure how much is there, or ask how long to let it set. A question that left me wondering what if was what would happen if we mixed the stains without rinsing. A way that we could of tested that question was to mix the dyes and just try it and learn from it.
