Teacher Site Map
8th Grade Core
Science Home Page
USOE

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

Materials

  • 500 ml. beaker
  • Thermometer
  • 2 g. quick rising dry yeast
  • 50 ml. 3% hydrogen peroxide
  • Spoon
  • Pen or pencil
  • Paper

Procedure

  1. Measure the room temperature using the thermometer.
  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 to 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:
  

 
Safety concerns: icon Be sure to follow all glassware, and chemical safety rules that are specified by your teacher in all general laboratory experiences. As with all science lab activities, the most important safety rule is to follow all teacher directions.

Analysis:

  1. What evidence did you observe that a chemical reaction had taken place?
  2. In what way did the temperature change?
  3. Which chemical changes did you observe?
  4. Which physical properties changed as a result of this experiment?
  5. How do you know that this was a chemical reaction and not the result of the yeast just growing and reproducing?

Review science lab safety 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: the title of the activity, the URL (Internet address), and your name. Remember that no pictures can be used which show any student faces or has a student name on it.

Updated August 13, 2005 by: Glen Westbroek

Science Home Page | Curriculum Home Page | 8th Grade Science Core Home Page | USOE Home Page

Copyright © Utah State Office of Education.