Halloween Science: Bloody Hand

Getting ready for Halloween can provide lots of fun science activities. This one involves turning your hand "bloody".

You will need:

Goldenrod Color-Changing Paper, ammonia cleaning solution, 3 wine glasses, baking soda, vinegar, phenolphthalein (extracted from laxatives as main ingredient).

Now try this:

1. Place your hand in cleaning solution and then imprint on the goldenrod color changing paper.

2. Remove hand and observe the blood red that is created.

3. Place baking soda and warm water into one wine glass, mix and allow to sit until solution turns clear.

4. Place a few drops of clear, colorless phenolphthalein into second wine glass.

5. Place vinegar into third wine glass.

6. Pour first wine glass containing baking soda solution into second wine glass containing the phenolphthalein. Observe the blood that is created.

7. Pour the second wine glass into the third wine glass containing the vinegar. Observe the blood disappear.

What is happening?

The goldenrod paper and the phenolphthalein are called acid indicators and are used to test the pH of substances. When solutions have a high pH both the paper and the phenolphthalein turn red. Ammonia and baking soda are two common household products that have a high pH. This means these substances are classified as bases (opposite of acids). The vinegar has a low pH and is classified as an acid which can change the color from red back to colorless.