Objective: To identify and demonstrate the effects of acid rain on statues.

Materials: vinegar, 10-ounce clear plastic cups, pieces of chalk

Background: The water cycle helps renew water as a pure resource. But the flow and cycling of water can also help spread pollution sources.

Acid rain is a prime example. Air pollution from industrial sources and automobiles releases sulfur oxides and nitrogen oxides into the air. When mixed with water vapor, they form sulfuric and nitric acids, which fall to the ground in the form of acid rain, snow, fog, or dew. Acid rain can cause damage to buildings, car finishes, crops, and forests. The major sources of acid rain are automobiles and coal-fired boilers at power plants and industries.

This acid precipitation can also pollute clean waterways through runoff. Increased acidity of water can negatively affect fish and other aquatic life. The effects of acid precipitation may not be felt for many months. Acidic snowmelt may create acid "shock" in a stream and cause serious fish kill in the spring.

The most cost-effective (and the only reliable) solution to the problem of acid rain is to control the offending pollutants at their source. The goal must be to emit fewer pollutants into the air so that fewer acids form in the atmosphere. Today power plants and industries emit a small fraction of what they did years ago. As pollution control technologies improve, and as society's commitment to environmental quality grows, we will emit even fewer acid-forming pollutants.

Procedure:
Show video to students and discuss what possible effects acid rain could have to each of them.

Have the students imagine they are on a trip to some mountains far away. They want to visit a beautiful lake they once saw in a picture. Describe a trip from where you are located to such a place. Tell the students that when they arrive at a lake, it looks even more beautiful than in the picture. The lake is deep, clear and very blue; it reflects the sky perfectly. Describe how quiet and serene it is here. Then introduce an ominous note by saying that it is "too quiet".

Describe how the students would start to notice that there are no fish jumping in the lake, no frogs croaking along the shore, and no dragonflies buzzing about the edge of the water. As they start to examine the lake, they find no living things in the water - just some old shells, insect cases, and dead moss. This lake is dead!

Continue the story by telling the students that just as they are discussing what happened to the lake, they hear someone coming. The students look for a place to hide, but before they can hide, Ranger Dave rides out of the forest on his faithful horse, Giddyup. He waves and smiles. The students are relieved. They crowd around as he climbs down from his horse, asking him about the dead lake. The ranger frowns, takes off his hat, and says only two words... "Acid Rain". What on earth does it mean? How could rain hurt the lake? How could rain be acidic? Ranger Dave shakes his head and drawls, "You folks best be getting back to class. The next lesson is about acid rain, and if you don't hurry, you're gonna miss it!"

Fill one plastic cup 1/4 full of vinegar.

Add a piece of chalk to the cup.

Bubbles should start rising from the chalk. Small pieces start to break off, and finally the chalk totally breaks apart.

Vinegar is an acid and acids slowly react chemically with the chalk. The piece of chalk is made of limestone, a mineral that quickly changes into new substances when touched by acid. One of the new substances is the gas seen rising in the vinegar, which is carbon dioxide gas. Acid affects all minerals, but the change is usually slow. The slow deterioration of statues and building fronts is due to the weak acid rain that falls on the statue. If the stone is limestone or has limestone in it, the deterioration is more rapid.

When acid rain falls from the sky, it affects the land or lake it falls on. The worse the problem, and the longer it goes on, the greater the effect. Over long periods of time, a lake's water can collect acid and other chemicals (e.g., metals that acid rainfall leaches out of soil around the lake) that are harmful to the living things in the water. If the problem becomes severe enough, the smallest animals and plants will die first; the larger animals will die. Finally, nothing will be alive in the lake.

Extensions:
Contact the EPA or your state's environmental protection office for information about acid rain.

Do an Internet web search and visit an acid rain site which gives you information about acid rain and what you can do about it.

Have students imagine that they are the governor of a state. They are having three major problems: 1) Industries are discharging over the allowable emissions from their sites into the air; 2) On the largest city's zoning agenda for this month is the city's plan to add 12 new businesses, each with it's own drive through; and 3) At the state's only state park is a lake that seems to have almost 50% of it's trees and vegetation dying. Have the students write ways they would take care of these concerns.

Vocabulary Glossary:
Acid: A kind of chemical; acid in food is sour, sharp, or biting to the taste
Acid rain: Rain with a pH of less than 5.6; results from atmospheric moisture mixing with sulfur and nitrogen oxides emitted from burning fossil fuels; may cause damage to buildings, car finishes, crops, forests, and aquatic life
Pollutant: An impurity (contaminant) that causes an undesirable change in the physical, chemical, or biological characteristics of the air, water, or land that may be harmful to or affect the health, survival, or activities of humans or other living organisms
Vegetation: Plant life
Grade Level:
4-6

Subject Areas:
Science

SD Standards for 4th grade:
Science
4.E.1.1; Nature of Science Indicator 2

Setting:
Classroom

Skills:
Recall, Observation

Prior Preparation: If possible, show video clips from a local weather video or "Earth At Risk, Environmental Video Series - Acid Rain" that shows the effects of acid rain on statues, vegetation and wildlife in your area. Have students research local newspapers to findout if acid rain or snow is a problem in your area.

Vocabulary:
acid, acid rain, pollutant, vegetation
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