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In our atmosphere, our air is made up of many different gases. The most common are Nitrogen (78%), Oxygen (21%), other gases (<1%), and water vapor in varying amounts. Some of  the other gases that have a big effect are Carbon Dioxide and Sulfur Dioxide that come from burning of fossil fuels. These gases in the air can, and do often chemically combine with metals in the earth such as iron, aluminum, copper, tin, silver and gold to form new compounds that look much different than their parent material. In the chemical reaction with iron nails the iron combines with the oxygen gas and the water vapor to form Iron Oxide which is also called rust. Sulfur Dioxide can combine with water vapor to form acid rain, which has become a worldwide problem.
 
Silver plates and other silver objects can react with the oxygen in the air to form tarnish. Other chemical compounds are used to take away the tarnish and help restore silver back to its original shiny state. Corrosion control is big business.
 
Try It!
Now it's time for you to try and oxidize a penny!
 

Materials:

  • One penny
  • Container (e.g. beaker or glass)
  • Paper towel
  • Graduated cylinder
  • Water
  • Vinegar
  • Watch, clock, or stopwatch
 
Safety concerns: icon Be sure to keep all glassware, and chemical safety rules. As with all science lab activities, the most important safety rule is to follow all teacher directions.
 

Procedure:

  1. At each step, remember to record your observations in your science journal.
  2. Place penny into container.
  3. Measure 50 ml. water using graduated cylinder.
  4. Pour water over penny.
  5. Leave penny covered with water for 15 minutes
  6. Remove penny from water and place on paper towel (do not dry off!)
  7. Leave penny to dry for at least 12 hours.
  8. Place penny back into container.
  9. Measure 50 ml. vinegar using graduated cylinder.
  10. Pour vinegar over penny and leave covered for at least 25 minutes.
  11. Observe penny and compare observations based on time while it is under the vinegar.
  12. Remove penny from vinegar and carefully dry off using paper towel.
 

Anaylsis:

  1. What changes occurred to the penny while it was under the water at the beginning?
  2. How did the penny change while it was drying?
  3. Why do you think that water was used in this experiment?
  4. What changes did you observe while the penny was under the vinegar?
    • How long did it take for you to see changes to the penny while it was under the vinegar?
  5. How did the penny you dried off at the end of the second part of the experiment compare to how it looked when you covered it with vinegar?
  6. What purpose did the vinegar serve in the experiment?

Review Science safetey rules here.

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Want to share photos of you or your friends doing this activity? Send it in an e-mail with the following information:

  1. The title of the activity
  2. The URL (Internet address)
  3. Your name.

Remember that no pictures can be used that show student faces or student names on it. 

Teachers should view the Teacher Site Map to relate Sci-ber text and the USOE 8th grade science core.


Updated October 24, 2008 by: Glen Westbroek

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