2. OBJECTIVES Observe an exothermic reaction. Differentiate between physical and chemical changes. Observe an exothermic reaction. Differentiate between physical and chemical changes.

3. You will use the 0 C of the thermomete r to take the temperature readings.

4. Place the thermometer in the jar and close the lid.

5. Wait about 5 minutes for the thermometer to record the temperature. While you wait for thermometer to record the temperature, soak a piece of steel wool in vinegar for 1 minute.

6. Squeeze the excess vinegar out of the steel wool. Seal the jar. Wrap the steel wool around the end of thermometer and place them in the jar.

7. Wait 5 minutes, then read the temperature and compare it with the first reading.

8. Did the temperature increase or decrease? What is the temperature difference? Did a chemical or physical change take place? Did the temperature increase or decrease? What is the temperature difference? Did a chemical or physical change take place?

9. OBJECTIVES Observe an endothermic reaction. Distinguish between a chemical change and a physical change. Observe an endothermic reaction. Distinguish between a chemical change and a physical change.

10. Fill the jar with room temperature water. Put the thermometer in the jar. Wait 5 minutes then take the water temperature. Fill the jar with room temperature water. Put the thermometer in the jar. Wait 5 minutes then take the water temperature.

11. While you wait to take the water temperature, put your hand on the outside of the jar and notice how cool or warm it is. RECORD YOUR OBSERVATION.

12. Record the temperature of the water after 5 minutes are up. Stir in the Epson salt. Fill the jar again. RECORD YOUR OBSERVATION. Record the temperature of the water after 5 minutes are up. Stir in the Epson salt. Fill the jar again. RECORD YOUR OBSERVATION.

13. Wait 2 minutes and record the temperature of the Epsom solution. Record the temperature. Wait 2 minutes and record the temperature of the Epsom solution. Record the temperature.

14. Did the water temperature increase or decrease? What is the amount of temperature difference of the water before and after adding Epsom salt? Did the water temperature increase or decrease? What is the amount of temperature difference of the water before and after adding Epsom salt?

15. Why did the temperature of the water change? Does mixing Epsom salt and water represent physical or chemical change or both? Why did the temperature of the water change? Does mixing Epsom salt and water represent physical or chemical change or both?