pH Test Lab
Problem:
Find the pH level of several substances.
Hypothesis:
The acidic substances will turn the litmus paper red and the basic substances will kepp the litmus paper blue.
Materials:
household solutions
vinegar
lemon juice
blue litmus paper
computer
Vernier computer interface
LoggerPro
Vernier pH sensor
wash bottle
distilled water
ring stand
sensor soaking solution
7 small test tubes
paper towel
stirring rod
red cabbage juice
250 mL beaker
diet soda
milk
graduated cylinder
small sticky notes
Procedures:
First, find goggles and wear them throughout the entire lab. Next, label the test tubes with what substance will be put in it. Then, fill the first tube will 3 mL of vinegar. Next, use the stirring rod to put a drop of vinegar on a strip of litmus paper. Next, try to match the color of the paper with colors on the pH scale. Next, record the information. Then, repeat these steps with every other substance. Then, put 3 mL of distilled red cabbage juice into the vinegar. Next, record the color that the liquid turned. Next, repeat these steps for the rest of the substances. Next, put the pH sensor into a test tube with vinegar. Then, record the pH level that LoggerPro stops at. Then, clean off the pH sensor. Next, repeat these steps with the rest of the substances.
Results:
| Substance | Blue Litmus | Cabbage | Sensor |
| vinegar | pH of 2 | pink | pH of 2.8 |
| ammonia solution | pH of 11 | green | pH of 11.3 |
| lemon juice | pH of 3 | pink | pH of 2.5 |
| diet soda | pH of 3 | orange | pH of 3.8 |
| drain cleaner | pH of 5 | yellow | pH of 12.6 |
| detergent | pH of 10 | green | pH of 9.6 |
| baking soda | pH of 9 | teal | pH of 8.4 |
| milk | pH of 13 | purple | pH of 7 |
Conclusion:
I accepted my hypothesis because the litmus paper and the cabbage juice turned warm colors when acidic and cool colors when basic. The litmus paper was accurate for the most part. The cabbage juice was accurate. The sensor was extremely accurate. This was a great and fun experiment.
