Science Buddies: "Ask an Expert"

Experiment: How storage temperature affects the pH levels in orange juice

Hypothesis: Greater temperature will cause the citric acid in the orange juice to dissociate. This will increase the availability of hydrogen ions, indicating a stronger acid and resulting in a lower pH number. The opposite effect will occur if the orange juice solution is colder.

TiagoPDS16,

Thank you for your question and welcome to the forum. In short, yes your hypothesis is testable. You need to make sure you control all your variables. For instance, your independent variable of temp, taking many measurements across a range of temps from very cold to warm. The measurements of your dependant variable of pH level will need to be measured very accurately as the change may be quite subtle. I would also suggest performing the experiment at least three separate times using juice from three separate cartons to prove repeatability and also determine an average amount of pH change per degree of temp change.