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Acids Eating My Nose
and other great lessons!

Background

Acid rain is more acidic than normal rain and forms through a complex process of chemical reactions involving air pollution. The two most important pollutants that contribute to acid rain are sulfur dioxide and nitrogen oxides, which react with moisture in the atmosphere forming acid rain. The sulfur and nitrogen compounds  primarily come from human sources, such as automobiles, industries and utilities.

Acid rain can have many disguises. It can fall as snow, hail, sleet, fog, it can even fall as dry particles. The true name for acid rain is really acid deposition, and can be classed as wet-deposition (rain, sleet, etc...) or as dry-deposition.

Acid rain can harm forests and crops by washing away nutrients and poisoning the plants. Bodies of water can have their pH altered so much that the aquatic life dies, or different, more acid tolerant, species take over. The corners of buildings can be slowly be eaten away, and statues can be smoothed as ears, noses, and any other parts that stick out are slowly dissolved.

Don't panic! Acid rain is not a strong enough acid to do you harm as it lands on your skin. Acid rain usually has a pH of about 5.4-5.6. Remember pure water has a pH of 7. If we compare acid rain to other everyday items we can see that it is not as acidic as a lemon (pH 2.2) or even an apple (ph 3.0).

Activity I: Acids Eating my Nose!

Purpose
To demonstrate the effect of acid rain on statues and buildings.

Objective
Students will learn how acid rain is an air pollution problem.

Materials

  • Clear cups, glasses, or jars
  • Chalk
  • Vinegar
  • Optional: Long nails (hammer and nail type, not finger nail)

Time
1 period

Procedure

  1. Explain that acids react chemically with limestone.

  2. Explain that vinegar is an acid and that chalk is limestone, or give your students pH paper and get them to assess whether vinegar is an acid or base.

  3. Give each group a piece of chalk, and you can choose to give them a long nail to scratch a design in the side of the chalk. I usually go with squiggly lines or the students initials. This will make their chalk unique, and will represent their statue.
  4. Add vinegar to the groups glass/cup/jar and ask them to drop in their statue, observing closely.

  5. Ask students about their observations.

  6. Ask students what would happen if they had used acid rain instead of vinegar. You may want to remind them at this point that vinegar is more acidic than acid rain.

  7. Ask the students if they should be concerned about acid rain? Why? How can we try and prevent it. (Remember the sources, factories, automobiles, and utilities). Answers should relate to driving less (carpool, bus, bike, walk), saving energy (turning off lights, lowering a.c.), and buying less stuff (the 3 R's: reduce, reuse, recycle).

Activity II: Acid Rain and Plants

Purpose
To demonstrate the effect of acid rain on plants

Objective
Students will learn how acid rain is an air pollution problem.

Materials

  • 4 Plants
  • pH paper
  • 4 Water bottles or spray bottles
  • Vinegar
  • Ammonia
  • Water
  • Measuring cup/cyclinder
  • 4 Labels
  • Pens

Time
1/2 hour on day 1. Then 5 minutes a day for about 2 weeks.

Procedure

  1. Explain to the students that they are going to do an experiment about acids, bases, and plants. What do they think will happen if we water plants with liquids of different pH's? What changes do they expect to see? How long do they think it will take for plants to change?

  2. Split students into 4 groups.

  3. Give each group a plant and a water bottle/spray bottle.

  4. Give each group their recipe for their liquid (see below).

  5. Ask the groups to label their water bottle and plant with their group number or allow them to create a group name.

  6. Ask the groups to take responsibility to water their plant each day and take notes on whether they notice any change in color, foliage, and health over the next two weeks.

  7. At the end of the two weeks, lead a discussion about the differences observed in the plants that they took care of.

  8. Ask the students if they should be concerned about acid rain? Why? How can we try and prevent it. (Remember the sources, factories, automobiles, and utilities). Answers should relate to driving less (carpool, bus, bike, walk), saving energy (turning off lights, lowering a.c.), and buying less stuff (the 3 R's: reduce, reuse, recycle).

Recipe for liquids

          Group 1-  water

          Group 2-  15 parts water, 1 part vinegar

          Group 3-  7 parts water, 1 part vinegar

          Group 4-  7 parts water, 1 part ammonia

Activity III: Icky Eggs and Puny Plants

Purpose
To demonstrate the effect of acid rain.

Objective
Students will learn how acid rain is an air pollution problem.

Materials

  • 2 jars
  • 2 large pieces of egg shell
  • 2 Paper Clips
  • 2 Leaves

Time
1 period

Procedure

  1. On the day before doing the lesson, place 1 piece of egg shell, 1 paper clip, and 1 leaf, into each jar. Then pour water in one jar and vinegar in the other. Do not label them.

  2. To start the lesson, show the students the two jars, and explain that you placed 3 identical things in each.

  3. Ask the students why do they think they look different.

  4. Have the students measure the pH of each jar.

  5. Ask why would the pH have anything to do with changing the egg and the leaf.

  6. Give the students some background information about acid rain, and then ask them why should we worry about acid rain, and how can we try and prevent it. (Remember the sources, factories, automobiles, and utilities). Answers should relate to driving less (carpool, bus, bike, walk), saving energy (turning off lights, lowering a.c.), and buying less stuff (the 3 R's: reduce, reuse, recycle).