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Previously in Sci-ber text, you learned that the temperature of a substance is related to the motion of the molecules. Your goal in this activity will be to obtain evidence to demonstrate that heat is involved in a chemical change. It could be as easy as observing a match being struck - but instead, let's try an experiment!


  • Thermometer
  • Room temperature water
  • Four grams Epsom salts
  • Spoon
  • Glass beaker
  • Thermometer
  • 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.


  1. Fill the beaker half full of room temperature water.
  2. Carefully, put the thermometer in the water.
  3. Allow the thermometer to reach a stable temperature (about one minute) then record the temperature of the water.
  4. Carefully stir in the Epsom salts.
  5. Record your observations.
  6. Check the thermometer and record the temperature of the liquid each minute.
  7. Continue to record the temperature until it becomes stable (does not keep changing.)


  1. How does the water temperature compare after the Epson salts are added to the water?
    • Why might Epson salts affect water temperature?
    • What type of a change does this demonstrate (physical or chemical?)
  2. Does the temperature continue to change after the Epson salts are added to water?
  3. How long does it take for the temperature to stabilize?

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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