Science Fair Projects with Everyday Stuff by Salvatore Tocci

Author:Salvatore Tocci
Language: eng
Format: epub
Publisher: Enslow Publishing, LLC

Experiment 3.2

PRESERVING THE FRESHNESS OF FRUITS

Materials

*vitamin C tablet

*wax paper

*large spoon or small hammer

*large glass jar

*measuring cup

*various fruits

*knife

*paper cups

*paper towels

*clock

*orange juice

Vitamin C not only plays a role in good health, it can also keep fruit fresh. You have probably noticed that apples, pears, bananas, and other fruits darken when they are peeled and exposed to air for a short time. Chemicals in these fruits react with oxygen. This reaction destroys cells in the fruit, causing them to turn brown. Vitamin C can slow down the reaction between the chemicals in the fruit and the oxygen in the air. As a result, the color and taste of the fruit are preserved. This is why chefs often squeeze a lemon or lime, which contain vitamin C, over a salad that contains freshly cut apples. In this experiment, you can determine if vitamin C is more effective in keeping one particular type of fruit fresh.

Fold a vitamin C tablet in a piece of wax paper. Crush the tablet by pressing down with a large spoon or small hammer. Transfer the crushed tablet to a large glass jar and dissolve it in 1 cup of water.

Obtain a variety of fruits, such as an apple, pear, and banana. Peel or skin each fruit. Cut two sections from each fruit and place each section in a different paper cup. All the sections should be the same size. Cover one set of fruit sections with the vitamin C solution. Be sure that you add the same volume of vitamin C solution to each fruit section. Cover the other set of fruit sections with plain water as a control group.

After five minutes, pour the solution and water down a drain. Blot the fruit sections with a paper towel. Place the sections on a clean paper towel. Note how long it takes for each section to begin to turn brown. Repeat the experiment several times. Record your data in a table like the one shown in Figure 11.

You can test orange juices to see if they are as effective as a vitamin C solution in preserving the freshness of fruits. This would be an indirect way of determining which juice contains the most vitamin C. The more vitamin C in a juice, the more effective it should be in keeping fruit from turning brown when exposed to air.

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