• Lemon juice
• Chewable vitamin C tablet
• Water
• Spoon
• Plastic cups - 3
• Variety of fruit: apple, peach, pear, or banana
• Knife (use with adult supervision only)
• Plates - 3
• Pastry brush

1. Crush the vitamin C tablet with the back of a spoon and dissolve it in half a cup of water.
2. Pour some water and lemon juice in separate cups and let all three liquids come to room temperature.
3. With a parent’s permission or help, cut up one or more types of fruit into pieces of nearly-equal size.
4. Quickly put some of each fruit on three separate plates and label the plates with the words water; lemon juice and vitamin C.
5. Using a pastry brush, paint the fruit platters with water, lemon juice or the vitamin C solution – according to the label on the plate.
6. Arrange the fruit so that the cut surfaces are exposed to the most amount of air.
7. Let stand at room temperature for an hour or more and observe what happens to the fruit on each plate.
   

The cells inside the fruit contain many chemicals, some of which are called aldehydes. When you cut the fruit, many of these cells are damaged and they release aldehydes. When these chemicals mix with the oxygen in the air they turn brown, and thus change the colour of the cut surface of the fruit.

Vitamin C, also known as ascorbic acid, is found naturally in citrus fruits, such as lemons and oranges. It can also be made artificially and put into vitamin pills. Either way, the chemical that slows down the oxidation of cut fruit is the mighty vitamin C! It is often added to foods as a preservative to interfere with the natural process of spoiling.

Compounds like vitamin C (ascorbic acid) that slow down the oxidation reaction of cut fruit also slow down oxidation reactions in the human body! Oxidation reactions can damage cells, proteins and molecules in the human body and plants. Getting enough vitamin C can slow or prevent this from happening. This is one of the reasons why vitamin C is so important.