The Glow-in-the-Dark Spark Measuring the Luminescence in Glow Sticks Sarah Maloney

Abstract This project tested how brightly glow sticks will glow at different temperatures. Typically, a glow stick will glow brighter when heated and duller when put in the cold.In this experiment five glow sticks were placed in ice water baths, five were kept in water baths at room temperature, five were placed in tepid water baths, and five were placed in hot water baths. The ice water baths were around 15°C, the room temperature baths were around 24°C, the relatively hot baths were around 35°C, and the hot baths were around 40°C. Each glow stick was placed in an opaque jar with water and then placed in the designated water bath. Each glow stick was allowed to equilibrate to the temperature, and then the luminescence was measured with a sensor that read out how many volts were in each glow stick. The results showed that when the glow sticks were placed in heated water, the amount of luminescence given off was significantly higher than when they were placed at any of the other temperatures. While the heated glow sticks average measured to be 9.2 volts, the ones that were relatively hot averaged 5.8 volts. The glow sticks at room temperature averaged 4.4 volts whereas the ones kept in ice water didn’t even measure on the sensor. The hypothesis that stated that glow sticks will glow brighter when heated up was supported.

Question Do glow sticks glow brighter in warmer temperatures or colder temperatures?

Hypothesis If the temperature at which the glow sticks are is made warmer, then the glow stick will give off more luminescence and the voltage of each glow stick will be higher because the heat makes the molecules in the glow sticks move faster, therefore creating a brighter glow.

Background Information The main chemical in glow sticks in luminol. Luminol is composed of carbon, hydrogen, nitrogen, and oxygen When an atom is excited the electrons go up in energy and energy levels. When they fall back down to their normal spot, they release energy in the form of light photons. The more heat applied to the electrons the more sped up they get, so when they fall back down to their normal energy level they release more light.

Materials Jar Sensor Water bath Ice bath Glow sticks

Procedure Assemble Sensor Set up water baths Set up each glow stick at its designated temperature

Independent Variable: temperature of water Dependent Variable: amount of luminescenc (voltage) given off by glow sticks Constants: jar, sensor, probe

Data for 40°C Water 43.6°C8volts 41.7°C10volts 42.6°C10volts 42.4°C9volts 43.1°C9volts

Data for 35°C Water 35.6°C7volts 35.4°C5volts 35.5°C6volts 35.8°C6volts 35.6°C5volts

Data for 24°C Water 25.9°C4volts 23.1°C5volts 23.0°C4volts 24.2°C4volts 24.6°C5volts

Data for 15°C Water 16.7°C0volts 15.9°C0volts 16.2°C0volts 17.1°C0volts 17.9°C0volts

Averages This graph shows the average voltage for each temperature of water that the glow sticks were placed in. Notice that the voltage of the glow sticks increases as the temperature increases. This suggests that when a glow stick is placed in a hotter temperature, it will glow brighter than when it is placed in a colder temperature.

Averages This graph shows the average voltage of the glow sticks at different temperatures with error bars. Notice that the error bars do not overlap showing that the results were accurate. This suggests that when the temperature is warmer, the voltage will be higher in the glow stick.

Trend This graph shows a trend that forms from the data of this experiment. The trend line of this graph shows that as the temperature of the water decreases, the voltage of each glow stick increases. This also verifies that the hypothesis was supported.

Inconsistencies Environment Defect in the water bath

Conclusion Question- Do glow sticks glow brighter at higher temperature or lower temperature? Answer- Glow sticks glow brighter at a higher temperature. The hypothesis was supported

References Casciato, C. (2010, July 16). Ten things to know if you’re going to Global Dance Festival. Retrieved January 14, 2011, from going_to_global_dance_festival_denver.php Chaplin, E. (2009, December 1). What Chemicals are in glow sticks? Retrieved October 6, 2010, from Demand Media Property website: The chemical reaction. ( ). How luminol Works. Retrieved October 7, 2010, from Discovery Company website: Chemiluminescence. (n.d.). Retrieved 2010, from JRank website: Leland, J. K., Nacamulli, L., & Yang, H. (2002). Chemiluminescence. In McGraw Hill Encyclopedia of Science and Technology (Vol. 4, pp ). McGraw-Hill. What does luminol do? ( ). How luminol Works. Retrieved October 7, 2010, from