pH Level Lab

STQ: What are the pH levels of different household items/how do they differ?

Hypothesis: I believe that most household items are going to be acids. I believe they differ, because they are different substances entirely.

Materials:

computer household solutions
Vernier Computer Interface 7 small test tubes
Logger Pro test-tube rack
Vernier pH Sensor blue litmas paper
wash bottles paper towel
distilled water stirring rod
sensor soaking solution red cabbage juice
250 mL beaker

Results:

Test Tube Solution Blue Litmas Paper Red Cabbage Juice pH

1 Vinegar 2.5 3.5 Trans. Pink 2.4
2 Ammonia 10 6 Green 11.5
3 Lemon 2 2 Pink 2.21
4 Soda 4 3 Orange 2.43
5 Drain Cleaner 8.5 5 Yellow 13.44
6 Detergent 9.5 6.5 Green 10.17
7 Baking Soda 8.5 7.5 Teal 7.92
8 Skim Milk 7.5 9 Purple 7.31


1.) Which of the household solutions tested are acids? The household solutions that are acids are Vinegar, Lemon Juice, and Soda what proves this is the pH sensor levels. Yes, others like Drain Cleaner and Detergent are below 7 ph level but, this is a guess having to do with the Red Cabbage Juice.

2.) Which of the solutions are bases? How can you tell? The household solutions that are bases are Ammonia, Drain Cleaner, Detergent, and Baking Soda. You can tell this because of the pH levels from the pH sensor, Red Cabbage Juice, and Blue Litmas paper evidence.

3.)What color(s) is red cabbage juice indicator in acids? In bases? The acids’ colors are as follows Vinegar->Translucent Pink, Lemon Juice->Pink, and Soda->Orange. The bases’ colors are as follows Ammonia->Green, Drain Cleaner->Yellow, and Baking Soda->Teal.

4.)Can Red Cabbage Juice be used as an indicator to determine strength in acids/bases? Explain. I do not believe that it can. According to our data it does show that some data it may be slightly accurate, but tests like the ammonia show that it wasn’t nearly as close as it should be. RCJ->6. Actual pH Sensor->11.5. A very big difference if I must say.

5.) List advantages and disadvantages of litmus and red cabbage juice indicators. Advantages->Can give a quick look at an item and show the pH level without looking at any technology. Easy and fast possibly takes maybe 30-60 seconds. Disadvantages->Not nearly as accurate as a pH level sensor. One use if you only have some litmus paper and misuse it, well, you don’t have anymore litmus paper!

Conclusion: Over the past two days we have been recording the pH level of several household substances. For example, Coca-Cola, Skim Milk, Vinegar, are just some of these items. We’ve used pH sensors to test how high or low the pH level actually is, and we also used Red Cabbage juice and blue litmus paper to see this also.. To get this we had 3mL of distilled water poured into a 250 mL beaker and then added 3mL of the Red Cabbage juice then poured it into one of the many substances and then tested the substance by dipping the litmus paper into the substance and then checking the color on a pH color chart. To get a more accurate read we poured the substance into a test tube and ran the pH level sensor and dipped it into the substance.
I see that my hypothesis is true assuming that the question is some sort of question, and not some sort of declarative statement. We had no problems in this lab what-so-ever it was simple, easy, and quick! I see that now if I ever wanted to check the acidity of my pool so that it is safe to swim in I can reassure myself and check whenever with this quick and easy method! I do not see any variables that could be changed to make this lab better.

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.