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Butterfly Pea Flower Tea, loose leaf tea, pitcher of lemonade, cut lemons

Test the pH Scale in Lemonade

The pH scale is how scientists measure the acidity of a base or a liquid. In our at-home laboratory—the kitchen—we can use a pH indicator to visually show us chemistry in action.

What Are Acids and Bases?

Most liquids are an acid or a base and the pH scale measures these two essential chemicals. Ions are located inside both acids and bases and they determine what’s what. If a liquid has a higher amount of hydrogen ions in it, it’s an acid and if a liquid has a higher amount of hydroxide ions, it’s labeled a base.

What Is pH?

pH is the potential of Hydrogen or power of Hydrogen and how scientists measure whether a liquid is acidic or basic (AKA base).

The pH scale ranges from 0 to 14. The numbers 0 to 7 are acids, with the strongest being 0. Bases range from 7 to 14, with 14 being the strongest base number. You might have noticed that the number 7 is included in both the acid and the base number range. What's up with that? That’s simply because the number 7 is neutral and neither an acid nor a base!

An example of a neutral pH would be drinking water. On the flip side, an acid that you may be familiar with is lemon juice, which has a pH of 2.4.

In Drinks or Foods, What Do Acids and Bases Taste Like?

Acids are usually tart or bitter tasting, which makes sense based on our lemon juice example from earlier. Bases, on the other hand, are typically bitter. An example of a base in baking is baking soda! When mixed into a recipe, they help make the end result wildly delicious.

How Does a pH Indicator Work?

A pH indicator is a substance that informs us if a liquid is an acid or base. Our experiment uses Butterfly Pea Flower Tea, which contains Anthocyanin—a natural pH indicator.

As the pH changes, the color of the indicator will also change. This is because it’s reacting to bases and acids. When reacting to bases, you’ll see a bright, beautiful blue. Then, when the tea is added to your lemonade—which we know is acidic—the color will change again. Can you guess what color it will change to? This is chemistry happening before your eyes!

Did You Know?
Did You Know?
  • When acids and bases mix, they neutralize one another and produce salts! This is called a neutralization reaction.
  • Natural pH indicators can be found in nature and include many flowers, fruits, vegetables and spices. When acidic solutions are detected, these substances will change color!
  • Common household acids include lemon juice, orange juice, vinegar, Vitamin C and apples. Acidic liquids also can conduct electricity.