This experiment is a continuation of our Butterfly Pea Tea Color Change STEAM Activity. During that experiment I explained to my kids that the dark color in the butterfly pea tea that is a pH indicator is also found in things like blueberries. My son immediately asked if we could try the experiment again using blueberries instead. I loved his curiosity and that he wanted to continue this experiment, so of course I said yes!
We basically followed the same procedure of the butterfly pea tea experiment, but substituted the tea with blueberries! Continue reading to get all the details and see how this experiment worked out compared to the butterfly pea tea.
Materials:
- 5-10 Blueberries
- Hot Water
- Mug or clear cup
- Fork
- Strainer
- Lemon
- Sugar or honey (optional)
Procedure:
- Measure about 2 cups water
- Put water into a tea kettle and bring to a boil
- Meanwhile, place 5-10 blueberries in a mug
- Add the boiling water to the mug and steep the blueberries for ~5 minutes. Once the blueberries are soft, mash them into the hot water using a fork. At this point the water becomes cloudy from all the blueberry pulp, so we strained the hot water into a clear cup (it is easier to see the color change in a clear cup).
- Squeeze lemon into the blueberry juice and watch it turn from light pink to bright red , the more lemon you add the more color change you’ll see. We started with a quarter lemon, but added up to a half lemon per cup.
- Add sugar or honey to taste, and enjoy your blueberry-lemon juice.
STEAM Concepts Learned:
Science: Like the butterfly pea tea, blueberries are colored blue by a pigment called anthocyanin. The anthocyanin is a pH indicator, so it changes color as the pH changes. It starts blue in its natural state as a base. The lemon juice is an acid. It lowers the pH, which causes the anthocyanin to change color as more lemon juice is added and the pH becomes acidic.
There were some big differences in the color changes that we saw in the two experiments. The butterfly pea tea started out as a dark blue color and changed to a bright pink when the lemon juice was added.
The blueberry juice (surprisingly to us) started as light pink once the blueberries were mashed and strained, and turned to a bright red color when the lemon juice was added. It was light pink instead of blue because while the outside of the blueberry is blue, the insides of the blueberries are white, so when mashed together it becomes a pink color! Both the tea and blueberries have the pH indicators but they just had different color changes.
I was so proud of my son for his interest in continuing our previous experiment. We really enjoyed this experiment, even though the color change is not as dramatic as it is with the butterfly pea tea.
And I believe this experiment is much more accessible to everyone – it’s easy to buy blueberries at any grocery store year round, whereas butterfly pea tea is a speciality item that is difficult to find.
Check out the Instagram Reel I made with all the experiment details below.
If you try this experiment please comment and let us know how it worked out for you!
