Sandra Oh Lin
What do cranberries and chameleons have in common? They can both change color! Cranberries contain chemicals called anthocyanins, which change color depending on how acidic their surroundings are. (They are natural pH indicators!) Since cranberries are naturally acidic, they normally look red, but we can neutralize the acid to find the berry's true colors.
How We Did It
Fill the cup halfway up with cranberry juice.
Add a spoonful of baking powder and stir. Watch out, it'll fizz!
Watch the cranberry juice change color. What does it look like now?You've neutralized the acid in the juice with a base, so the anthocyanins changed color. Think you can change it back?
Change it Back:
Add a little bit of citric acid or lemon/lime juice to the cup. (It'll fizz again!)The juice should start changing color. If it is not fully changed, add a little more acid.
Congratulations! You gave the juice its color back! The juice is acidic again, so the anthocyanins have turned back to red.
You can get other colors out of your cranberry juice by using different acids and bases. Try using vinegar, or cola, or baking powder. What colors do you see?