I love my apple slicer. Like the apple slices in the photo, I press the slicer into an apple and voila’ I have nice slices that spread out like flower petals. Even the apple core makes a decorative center for apple “petals.” But, the apple slices must be eaten in a short period of time or they start turning brown.
A observation like this can be the start of a great science fair project. When you see changes, such as apple slices turning brown, record facts you know as well as your ideas about the cause of the change. For example:
Why do sliced apples turn brown?
1. Fact: Color changes are often a clue that a chemical change has occurred. Question: But, how could slicing an apple cause a chemical change?
2. Fact: When an apple is sliced the part not covered by the peel is exposed to air. Air contains oxygen. Oxidation is the name of the chemical reaction when something combines with oxygen. Question: Is there a chemical reaction between the chemicals in the apple and oxygen? In other words, does oxidation cause the apple to turn brown?
4. Fact: My mom squeezed lemon juice on fresh fruit salad to prevent browning. Lemons have citric acid. Questions: Does citric acid prevent the browning?
Photo from Theilr