pH'ing in the Kitchen, part 2

pH’ing in the Kitchen, part 2

Making pH indicator test strips from red cabbage.

In the previous video, pH’ing in the Kitchen, part 1, I showed how to make a pH indicator from red cabbage. pH indicators are used to test acids and bases. Red cabbage is an example of a pH indicator that we can use to make pH test strips at home. The test strips change color when an acid or base is detected.

In this video, I show how to make pH indicator test strips from red cabbage juice and coffee filters. I used my pH test strips to test the acidity and basicity of foods found in my kitchen. The change in color of each test strip varied based on the acidity or basicity of the foods tested.

Parental supervision is highly recommended for this activity.

This activity was created exclusively for STEAMfest by Shannon Blakely a Woodlawn parent.

pH indicators measure the amount of hydrogen ions present. The more hydrogen ions present, the more acidic, and the lower the pH. The less hydrogen ions present, the more basic, and the higher the pH. When used to test foods and other substances, pH test strips vary in color based on that presence or absence of hydrogen.

Additional items that could be used for testing (the Internet is a useful tool for suggestions as well):

Apple
Orange
Tomato
Potato
Garlic
Soybeans
Other fruits or vegetables
Egg white
Egg yolk (yes, they have different pH’s)
Nut/Seed butters
Soda
Bicarbonate
Salt
Sugar
Dish soap
Toothpaste
Alka Seltzer

Handy items useful for prepping foods:

Garlic press for pressing out juices
Potato peeler
Water for dissolving items

Journal Questions

How many items did you test with your pH indicator test strips? If you have a picture from your own experiments with your homemade pH test strips or a picture of your completed downloadable worksheet, please share. We’d love to see your results!
Hopefully, your pH test strips varied in color depending on the item tested. What color was your favorite test strip and what was the food that produced that color?
Did you test any items not listed in this activity? If so, what else did you test and what did you find? If you didn’t test anything new, did you find a pH change that surprised you? If so, tell us what the item was and what surprised you?

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