- 1/2 cup of blackberries
- 1/4 cup of water
- 2 tablespoons of dish soap
- 1/4 cup of vinegar
- Bowls or other containers
- White construction paper
- Paper towels
- Zipper lock bag
- Remove any stems or leaves from your berries and place the berries in a zipper lock bag.
- Zip up the bag and mash and mush your berries until they look like jam.
- Add a small amount of water to thin the juice a bit.
- Mix it all up and pour your berry liquid into a bowl.
- Cut some thin strips of the white construction paper and dip them into your mashed berries. Push the strips all the way into the berry mush to make sure they are good and coated with the juice.
- After taking your “berry” well-soaked paper out of the juice, pull the strips between your thumb and index finger to remove any excess juice and pulp.
- Lay the strips onto paper towels and allow them to dry.
- Once your paper strips have dried, carefully pick off any large pieces of pulp or berry skins. You’re ready to use your Berry pH Paper.
Putting Your “Berry” Own pH Paper to the Test
- Pour 1/4 cup of water into a bowl and mix in two tablespoons of dish soap.
- In a separate bowl, pour 1/4 cup of vinegar.
- Dip half of one strip of your Berry pH Paper into the bowl containing dish soap and water. Do the same thing with another strip of Berry pH Paper, but this time dip it into the vinegar.
- Set the Berry pH Paper strips onto a piece of paper towel to dry. This should only take about five minutes. Make sure you label the pH strips to remember which strip was dipped in which liquid.
- What color changes did you notice? Which liquid was an acid? Which liquid was a base?
Cool… but how do I use it?
Blackberry pH Paper turns pinkish red in acids and turns deep purple in bases.
How does it work?
Blackberries, blueberries, strawberries, and a bunch of other flowers, leaves, and stems are naturally occurring pH indicators. This is true because they contain chemicals from the anthocyanin family of compounds. Anthocyanin compounds turn red in acids and blue in bases when they are in their pure form. In this case, we have the anthocyanin compounds within the juice of the berries. This results in a less distinct, but still distinguishable, color change.
Try testing out other liquids like milk, soda, or fruit drinks to find out which ones are acidic and which ones are basic.