Type

Grade

2^nd – 4^th grades 

Difficulty of Project

Cost

Less than $5.00 

Safety Issues

Material Availability

Readily available or can be easily purchased at a grocery store. 

Approximate Time Required to Complete the Project

One day to collect data; another day to write results and prepare the science fair display. 

Objective

To observe the effect of an acid on chalk to draw conclusions about how acid rain can cause rocks to erode 

Materials and Equipment

• 2 small clear drinking glasses
• Masking tape
• Pen
• 1 cup vinegar
• Measuring cup
• 2 pieces of white chalk 

Background Information

All rain has some acid. However, in places where large amounts of smoke are released into the air, gases such as sulfur dioxide and nitrogen dioxide are released from smoke into the air. In the air, these acidic gases become water droplets that make up clouds. Then these acids are released in the form of rain back to the earth. Acid rain harms the environment by killing seeds and eggs of many plants and animals. It also wears away rocks. 

In this project, the affect of acid rain is simulated by the acid, vinegar. Chalk is a soft rock made from limestone. This investigation will show in a short time what acid rain can do to rocks over a long period of time.

Terms, Concepts, and Questions to Start Background Research

Terms

acid: a chemical substance that can cause erosion 

acid rain: rain that contains a significant amount of acid usually in the form of sulfur dioxide and nitrogen dioxide from smoke in the environment

erosion: the process by which the surface of the earth is worn away by the natural actions of wind or water  

Concepts

Vinegar is an acid. Chalk is made from a soft rock called limestone. Gases from smoke are released into the air. In the air, the acidic gases become water droplets which return to the earth as rain.  

Research Questions

• What gases does smoke release?
• Where does smoke come from?
• How does the gas from smoke form into water droplets?
• What harm does acid rain cause? 

Experimental Procedure

1. Gather the necessary materials.
2. Label the first glass “Water” and the second glass “Vinegar.”
3. Pour one cup of water in the glass labeled “Water.” Pour one cup of vinegar in the glass labeled “Vinegar.”
4. Stand a piece of chalk in each of the glasses so that half of the chalk is in the liquid and half of it is out of the liquid. Place both glasses in a safe place overnight.
5. The next day, look at the glasses. Notice the difference between the two pieces of chalk. Record the results.  

Bibliography

Articles

“Acid Rain” at the Young People’s Trust for the Environment website 

“Weathering and Erosion” by Phil Medina at www.mrsciguy@optonline.net 

“How Acid Rain Works” by Sarah Dowdey at http://science.howstuffworks.com/acid-rain.htm 

Websites