Age Level:8-16
Subject: Social studies, science
Skills: Inferring, observation, measuring pH
Time: Several observations over 2 weeks. (3wks if use plants)
Group Size: Any
Setting: In or Outdoors 

The green links are vocabulary words. Click on the link to read the definition.

Objective: You will know the difference between an acid and a base. You will be able to describe the cause and effects of acid rain.

Background: In many places around the world acid rain is causing problems for plants, animals, lakes, rivers, and even old buildings. Pollutants such as sulfites are released into the air and "mix" with rain as it falls producing a mild acid, acid rain. The rain burns plants that need the rainwater to survive. Lakes and rivers die when they become so acidic plants and animals can not live in them. Acid rain can be so strong it burns the stone of old limestone and marble buildings.

Acids corrode things. You can create and example of corrosion by putting an iron nail (not steel or galvanized) in a glass of dark cola or put a piece of chocolate in vinegar. Acids are measured on the pH-scale. It is a scale from 1-14. One is the most acidic, 6 is close to neutral. 7 is neutral, distilled water is neutral. Battery acid is a1 on the pH scale. It would burn if you got it on your skin. Acids feels like water if you rub it between your fingers. A base is rates from 8 to 14 on the pH-scale. A base will feel slippery when you rub it between your fingers. Dish soap is a mild base. These chemicals should only be used when an adult is there to help you.

Materials: 2 small pans, 2 plant spray bottles, many strips of pH paper*, water, sunlight, local rain water or snow melt water, 2 small house plants r outdoor plants. If possible find fruticose or foliose lichens, collect them and put in the pans. Optional Materials: Hand lens, chocolate, vinegar, iron nail (not steel or galvanized), ammonia, lemon juice, soda, and distilled water. *pH paper can be purchased from any science supply or water treatment company.

Procedure: Mix 2 tablespoons of white vinegar per cup of water (1tbsp of wood ashes can be substituted for vinegar) and pour into one of the plant spray bottles. Label it "rainwater 1." Fill the second bottle with distilled water. Label it "rainwater 2." Suggestion for fun: Have an adult or someone else fill the plant spray bottles so you do not know which is the distilled water or the acid.

2. Place 2 lichen or plant samples in separate pans in a sunlit area. Label on pan "plant 1" and the other "plant 2." Put "rainwater1" with "plant 1" and "rainwater 2" with "plant 2." Do not mix the bottles, only use 1 with 1 and 2 with 2. Water the lichens every other day or the plan twice a week. 

3. Keep a journal, or use your Ranger Notebook to write what you predict will happen to the lichens or plants. Check the plants as you water them or more often. Record your observations in your journal or notebook. Use a hand lens to get a closer look at what is happening to the lichens or plants.

4. At the end of 2 weeks (3 with house plants) make a final observation. Look back at your predictions when you started the experiment, did they happen? Which bottle do you think had the "acid rainwater" in it? How did the acid rainwater" effect the lichens or plants?

5. When it rains collect rainwater in a container, do not get water dripping from your house. Sample the pH. Is it acidic, basic or neutral?

6. Walk around your neighborhood and look to see if any of the plants in your community are suffering from acid rain. What can you do to help stop acid rain? Share your answer with others.