ShareChanging Matter - Brrr...It is Cold!
In the Moving Molecules page of 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!
Materials:
- Thermometer
- Room temperature water
- 4 g. Epsom salt
- Spoon
- Glass beaker
- Thermometer
- Pen or pencil
- Paper
Procedure:
- Fill the beaker half full of room temperature water.
- Carefully put the thermometer in the water.
- Allow the thermometer to reach a stable temperature (about one minute) then record the temperature of the water.
- Carefully stir in the Epsom salt.
- Record your observations.
- Check and record the temperature of the liquid each minute.
- Continue to record the temperature until it becomes stable (does not keep changing.)
Safety concerns: 
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:
- How does the water temperature compare after the Epson salt is added
to the water?
- Why might Epson salt affect water temperature?
- What type of a change does this demonstrate (physical or chemical?)
- Does the temperature continue to change after the Epson salt is added to water?
- How long does it take for the temperature to stabilize?
