Article: To make your own pH indicator, you will need half a head of red cabbage, a knife, water, a stove, and a medium saucepan. Red cabbage contains a chemical called anthocyanin that changes color based on acidity. By boiling the cabbage, you can make a pH indicator from this chemical and test the acidity of your rain. Adult supervision is recommended for this because you will need to handle a hot stove and a sharp knife. . You want about 2-3 cups of red cabbage cut into small pieces. If you are young, have an adult help you with this step to avoid potential injury. The exact amount of cabbage is not important, so just cut up half of the head of cabbage. Place the chopped cabbage into the saucepan and add enough water to cover the cabbage. Put the saucepan on the stove and bring the water to a full boil. Once the solution boils, turn the heat off and let the water cool to room temperature.  Have a parent help with this step to avoid injury when using the stove and working with boiling water. You should notice that the water is now purple. Pour the cabbage and water mixture through a strainer into a bowl. The purple water (the indicator) is currently neutral because the water from your tap is neutral. In the presence of an acid, the indicator turns pink. In the presence of a base, the indicator turns blue. You can refrigerate the solution until you need it. To make sure the indicator is working properly, you can test it using baking soda and vinegar. Put 1 teaspoon (~5 mL) of the cabbage water into two small, clear glasses. Add a teaspoon of vinegar to one glass and a teaspoon of baking soda to the other.  Vinegar is acidic, so the water will turn pink. Baking soda is basic, so the water will turn blue. Collect some rainwater in a clean, plastic container. Pour 1 teaspoon of cabbage water into a small, clean glass. Add a teaspoon (~5 mL) of the collected rainwater to the cabbage water. The water should turn pink because all rain is slightly acidic. The deeper the pink, the higher the acidity in your area. This method will not tell you the exact pH of the rain, but will give you an idea of how acidic it is. If you are traveling, you can compare rain from different areas such as different cities, state or province, or even countries and see if the deepness of the pink changes.

What is a summary?
Gather the necessary materials. Chop up some cabbage Boil the cabbage. Strain out the cabbage and save the water. Test the indicator. Test the acidity of your rain.