Science class
Simply put, acids are corrosive and bases are slippery. When mixed together, they lose their normal properties and become more neutral. Conducting activities about pH levels will increase comprehension of acids and bases, and will allow students to understand how different substances, such as pool chemicals, work together.
The pH scale indicates the level of acidity and alkalinity. It ranges from 0 to 14; acids range from 0 to 6 on the scale, pure water registers at 7, and bases register from 8 to 14.
Cabbage Juice Indicator
Create a pH indicator with red cabbage juice and test the common household items such as vinegar, laundry detergent and baking soda. For this experiment you will need distilled water, cabbage, a dropper, a pot, strainer, clean containers and the previously mentioned household items.
Create the cabbage juice by grating a head of cabbage and boiling it in water until the water has turned a deep purple color. Strain the liquid and set aside in a container.
Add each household item to its own container and add some distilled water. Test the acidity by adding a few drops of cabbage juice to each solution. Acids will change to a pink color, while bases will turn greenish. You should find that the vinegar was an acidic solution while the laundry detergent and baking soda were both bases.
Writing Secret Messages
Write a secret message onto thick paper using acids and bases. Dip a cotton swab into lemon juice and write a secret message or a symbol onto a piece of thick paper such as cardstock or chart paper. Set the paper aside and allow it to completely dry.
Decode the message by lightly spraying the paper with cabbage water solution. The cabbage juice will react with the" ink" and make the message appear on the paper.
Test out other types of inks by dipping a cotton swab in other solutions such as dish soap or vinegar. Determine whether acids or bases make better inks.
Test pH of Water Samples
Measure the levels of acidity of different types of water and hypothesize why their levels are as such. For this experiment you will need water samples from several sources such as the tap, a pool or spa, pond, fish tank, bird bath and bottled water.
Gather a sample from each location into a vial or small container and label appropriately; strain out any debris from the water sample. Test the pH level of the water sample by adding five or more drops of cabbage juice and note any color changes. Compare the results to each other and note the differences.
Why would water from a dirty fish tank be a different color than water from bottled water? What are the possible implications? Theorize what could be added to create a more balanced pH and why that would be important.
Tags: cabbage juice, acids bases, baking soda, bases will, bottled water, cotton swab, detergent baking
