2. Goals Determine and understand the types of energy in this system. Follow the scientific method. Determine under which conditions that glow stick is brighter, lasts the longest and why.

3. Energy Energy can never be ___________ or ____________ Energy changes from one form to another! 1. Gravitational potential 2. Elastic 3. Chemical potential 4. Radiant 5. Thermal 6. Kinetic (motion) 7. Sound

4. What’s In a glow stick?

6. Before the Experiment What type of energy in an unbroken glow stick? 1. Gravitational potential 2. Elastic 3. Chemical potential 4. Radiant 5. Thermal 6. Kinetic (motion) 7. Sound

7. Hypothesis What do you think will happen? In what condition will the light will be the brightest or dimmest? In what condition will the light last the longest?

8. Methods 1. Break the glow sticks 2. Shake the glow sticks 3. Stick one each of the different water temperature Ice water Room-temperature water Hot water 4. Wait 1-2 minutes and record what you see in the table!

9. Data Glow StickObservations: What Do You See? Brightness Rank (1-3)*** Ice Water Room Temperature Hot Water

10. Results: After the Experiment What type of energy in a glowing glow stick? 1. Gravitational potential 2. Elastic 3. Chemical potential 4. Radiant 5. Thermal 6. Kinetic (motion) 7. Sound

11. Results: After the Experiment What type of energy is shown in the different water temperatures? 1. Gravitational potential 2. Elastic 3. Chemical potential 4. Radiant 5. Thermal 6. Kinetic (motion) 7. Sound

12. Class Demonstration Is the glow stick liquid in the ice water still glowing? Is the glow stick liquid in the hot water still glowing?

13. Theory The chemicals reacted  formed new chemicals. These chemicals do not need as much energy to hold their molecules together, so they release that extra energy as light.

15. Forming new chemicals and new bonds!

16. Theory When you put the glow stick in cold water, the cold water absorbed some of the thermal energy from the glow stick, so the reaction slowed down and the glow stick wasn’t as bright. Heat

17. Theory When placed in hot water, the chemicals in the glow stick absorbed the thermal energy from the hot water. The added energy made the chemicals react faster and produce more light. Heat

18. Conclusions 1. Describe how the energy changes types? Hint: Chemical, Thermal and Radiant Energy 2. In the experiment that you performed, how does temperature affect the brightness at the beginning? Sentence starter: As the temperature increases, the brightness… 3. In our class model system, how does temperature affect brightness after a long time? Sentence starter: As the temperature increases, the brightness… 4. Why does a reaction happen faster? Hint: Remember C-D-D and W-E-E?