Drop experiment

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WEEK 1 Part III the 5 Sec Drop Experiment

1. Make a hypothesis and prediction based on the 5 seconds food drop rule. Keep in mind a single variable when you develop your prediction.

Based on The five seconds food drop rule which states that food dropped on the floor will not be contaminated the first five seconds of being dropped, we can predict that after these five seconds the bacteriawill contaminate the food and the amount of bacteria will increase as the time passes.

2. Work in pairs and label the agar plates you will need. Each pair will get one nutrient agar and one blood agar plate. The plates can be divided in half so that two samples can be plated. Control bologna and gummy bear plates will be set up in class and you will not have to do your own. Your TA will makethe control plates with samples taken directly from the package and placed on the agar surfaces.

3. Make an experimental plan and get it checked by your TA before you proceed. You can sample with bologna, gummy bears, or a food of your choice. And you can test any surface you want Pleas remember to control you variables! For example, you can sample with the bologna by removing a piece whitsterile forceps and then place it on the test surface like the floor or couch. Count to 5 second and pick I up. It is best if you keep holding an edge with the forceps. Then place the surface that touched the floor or couch on the agar surfaces for 5 second. Place the top back on the Petri dish and throw the bologna away. You must repeat this procedure for each of the two types of agar-nutrient andblood. If you use the gummy bears, then take one from the Petri dish with the forceps and place it on the test surface for 5 seconds. Carefully pick it up and streak the agar surface with the side of the gummy bear that was on the floor or couch. Quickly close the Petri dish and throw the gummy bear away. Again, repeat this procedure for the second type of agar. Use table 1 to help organize yourmethods.

TABLE 1 MICROBOLOGY EXPERIMENT SET-UP

PLATE # AGAR TYPE SAMPLE SURFACE TREATMENT
1
One Half Nutrient Gummy Bear Lab Table 1 S
1
Second-Half Nutrient Gummy Bear Lab Table 50 S
2
One Half Blood Gummy Bear Lab Table 1 S
2
Second-Half Blood Gummy Bear Lab Table 50 S
3
Control (TA prepares) Nutrient Gummy Bear None None
4
Control (TA prepares) Blood Bolloni None None4. After your TA checks your plan, then get you agar plates and label them carefully. Do your food sampling and put the inoculated plates where they belong for your class section. All the plates will be incubated at room temperature until the next lab period.

5. It is possible that a few of the bacteria that grow and form colonies on these agar plates could cause disease, so the Petri platesshould always be kept closed. The majority of bacteria do not cause disease. So how do we get sick and why does it seem like families and friend will acquire diseases from each other? Scientists have found that the gratest transfer of bacteria es via the hands. Remember to wash yor hands!

WEEK 2 PROCEDURE Part I Learning About Disease Procedure Through Simulation

1. Do you get the exact sameresults each time? How do the results compare to each other.

The results are not the same each time. The results change because people get sick depending on many different variables. First you have to considerate the virulence of the microorganisms. Its also important to take into account the immune system of each individual, depending on this the microorganism will be able to break down thedefenses of the immune system or not.

2. How do the results compare to your prediction?

Some of the results are lower to the prediction and others are higher. It’s really difficult to get a really good prediction of how many people it’s going to get sick because of the different variables that might change the results, as the ones mentioned before.

3. What factors might contribute to...
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