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Whenever a chemical change occurs, there are often changes in the physical properties of the substance that underwent the change. Remember how different a fried egg looks from the raw egg? In this activity, you are going to measure the temperature and see how this physical property changes as a result of a chemical change.
 

Materials

  • 500 ml. beaker
  • Thermometer
  • 2 g. quick rising dry yeast
  • 50 ml. 3% hydrogen peroxide
  • Spoon
  • Pen or pencil
  • Paper
 
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. Measure the room temperature using the thermometer.
    • Record this temperature in the table below.
  2. Place the thermometer in the beaker (you may need to hold it carefully to keep it from falling over.)
    • Make sure you can read the temperature easily.
  3. Pour the Hydrogen Peroxide into the beaker.
  4. Make sure that the temperature shown on the thermometer is stable then, record the temperature.
  5. Quickly use the spoon to stir the yeast into the hydrogen peroxide.
  6. Observe what happens for five minutes. (Make sure you record your observations.)
  7. Make sure that you feel the lower sections of the beaker.
  8. Take the temperature of the mixture.

Sample Data Table:

Room Temperature:
 
Hydrogen Peroxide Temperature:
 
Observations:


Mixture Temperature:
 
 

Analysis:

  1. What evidence did you observe that a chemical reaction had taken place?
  2. In what way did the temperature change?
  3. What chemical changes did you observe?
  4. What physical properties changed as a result of this experiment?

Review Science safetey rules here.

Get the plug-ins: Get Adobe Acrobat Reader , and Get Quicktime Player. (The QuickTime plug-in is needed to play sounds and movies correctly.)

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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