September 21, 2018

Dilution and Experimental Design

The purpose of this lab was to learn the process of dilution; a very important technique that is used in biology labs. Dilution allows us to reduce the concentration of a solution. We reduced the concentration of ciliates in 900uL of a liquid. The other purpose of this lab was to create a question, hypothesis, and experimental design to use to test the effect of microplastics on tetrahymena.

Description:

1. There was one well with the concentrated, undiluted sample of tetrahymena in it.
2. There was tetrahymena culture media in a separate container.
3. Using a 1000p micropipettor, we took 900uL from the tetrahymena culture media.
4. In 4 wells, we put the 900uL of media.
5. Then, we discarded the tip of the micropipettor, and switched to a 200uL micropipettor.
6. Using this new micropipettor, we took 100uL of the concentrated, undiluted sample of tetrahymena, and put it in the first well with 900uL of media.
7. We discarded the tip and took 100 uL of media + tetrahymena from the first well and put it in the second well.
8. We continued these steps, finishing at the fourth well.
9. We put the 24 well plate under the dissecting microscope and observed the differences in concentration of each well.
10. We then chose a well that had a good amount of tetrahymena in it and put 5uL of it onto a concavity slide and put it under the compound microscope at 4X and 10X
11. I chose the 1e-1 dilution
12. Count the cells under the 10X setting and record how many are there.
13. After completing this, we cleaned our spaces, put everything back, and went to the computer lab.
14. This is where we created a question, hypothesis, and experiment for the effect of microplastics on tetrahymena.
15. My group decided to create an experiment about the effect of microplastics on structural development and reproduction of tetrahymena.

Data:

Notes:

Each person stored and labeled a sample of soil in a bin in the back of the room.

Next Steps:

After learning how to dilute and after creating a hypothesis and experiment, the next steps would be to test the experiment, possibly even using dilution as a way to do it. We need to get the right materials necessary for an experiment with microplastics and tetrahymena and we need to figure out which experiment we will be testing.