Yeast Beast

Lab Name: YEAST BEAST

Question: If yeast is added to an acidic, a neutral, and a basic mixture containing hydrogen peroxide, which will have the greatest reaction?

Hypothesis: I believe the basic mixture will have the highest reaction because there is less oxygen molecules for the yeast to react with.

Materials:
computer w/ Logger Lite
Vernier Computer interface
Vernier Gas Pressure Sensor
1-hole stopper
10mL graduated cylinder
3% hydrogen peroxide
3 test tubes w/ test tube rack
dropper
acidic mixtures (Coca-Cola)
neutral mixture (milk)
basic mixture (stomach antacid)
yeast suspension (water)
goggles
sticky notes

Procedures: Goggles are put on for safety. The Vernier computer interface and Gas Pressure Sensor are plugged into the computer and the file “24 Yeast Beast” in the “Middle School Science with Vernier Folder” is opened in the program Logger Lite. Three test tubes being held by a test tube rack are labeled by sticky notes to indicate which test tube is holding the acidic mixture, which test tube is holding the neutral mixture, and which test tube is holding the basic mixture. After that each test tube is filled with 3 mL of hydrogen peroxide, 3 mL of Coca-Cola acidic mixture is added to the acidic tube, 3 mL of the milk neutral mixture is added to the neutral tube, and 3 mL of the stomach antacid basic mixture is added to the basic tube. Water is added to yeast and is stirred until it becomes an even mixture. The dropper is used to suck in the yeast solution and drop two drops of the solution in to the acidic mixture, avoiding having the yeast touch the sides of the tube. Once the yeast is in the tube, the small rubber stopper is twisted tightly in and the liquids inside are swirled together inside the tube. Once they seem to mix, the tube is set back in the rack and the plastic tube attached to the Gas Pressure Sensor is connected to the stopper. Once it is attached “Collect Data”is clicked in Logger Lite, and it is being made sure that the test tubes are not shaken while the data records for two minutes. Once the data is done with collection the tubing is taken off of the stopper, which is promptly taken off the acidic mixture test tube. “Store latest run” is then clicked in Logger Lite and the same steps for testing gas pressure are repeated for the neutral and basic mixtures and the greatest air pressure in kPa for each test is recorded.

Results:

This picture is of the three test tubes before the yeast was added. In order from right to left, Acidic, Neutral, Basic

This is the first solution mof Coca-Cola being tested the amount of Yeast Activity and Pressure in the test tube.

This is the final result of yeast being added to all three of the test tubes.

This is the graph of the Pressure per solution and Yeast activity per activity.

Conclusion: I see now that my hypothesis is not true through looking at evidence given. My hypothesis is actually the exact opposite of the right answer! I actually am assuming we did not have any problems with the lab because I was not present the day of it, due to sickness. I also am not able to foresee any other situations where this could be helpful. Suggesting to use more yeast in the next lab could possibly have a different outcome in some way.