Vitamin C Titration Test

Project Overview: Not all juices are created equal, at least not when it comes to vitamin C. This project uses a real laboratory technique called titration to measure and compare exactly how much vitamin C is hiding in different drinks, using a color-changing starch indicator.

Materials Required:

1. Iodine solution

2. Cornstarch

3. Water

4. Several juices to test (orange juice, lemon juice, apple juice, a vitamin C tablet dissolved in water)

5. A few small clear cups

6. A dropper or spoon

Instructions:

1. Mix a tablespoon of cornstarch into a cup of water, then heat it briefly (or mix it into warm water) to create a starch solution and let it cool.

2. Pour a small amount of the starch solution into several separate cups, one for each juice you plan to test.

3. Add a few drops of iodine to each cup and stir. The solution will turn a dark blue-black color.

4. One drop at a time, add your juice sample into a cup, counting each drop and stirring gently after each one.

5. Keep counting drops until the blue-black color completely disappears, and record the number of drops it took for each juice.

Congratulations, you just performed a real analytical chemistry test.

Fun Fact: The fewer drops of juice it takes to clear the blue-black color, the more vitamin C that juice contains, since vitamin C is what's neutralizing the iodine. Freshly squeezed orange juice usually wins by a landslide.