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This article describes how by using three points to make a line and comparing the graphs for water and oil, students can mathematically demonstrate that Gatorade dissolves in water much more readily than in oil. Students can also use units to understand and solve a multi-step problem by observing the color of each solution, making conductivity measurements, and making a line of best fit to conclude that Gatorade contains hydrophilic compounds. This activity addresses the "Next Generation Science Standards" (NGSS Lead States 2013).

Sunscreens have different levels of protection, measured most commonly with the sun protection factor (SPF). Students initially believed higher SPF factors mean greater sun protection and learned through this activity that higher SPF does not mean greater protection. Students analyzed the amount of ultraviolet radiation (UVR) protection and composition of different sunscreens, first by UVR sensors in an outdoor activity and then by thin layer chromatography. These activities demonstrated that even some sunscreens provide protection from harmful UVR, and that different sunscreens, despite varying SPF factors and brand names, have similar composition. Students can apply their knowledge outside the classroom on outdoor safety and solar protection.

Understanding methane (CH4) fluxes from rice (Oryza sativa L.) at the field scale is paramount to reducing environmental impacts while ensuring global food security. Greenhouse gas (GHG) measurements at the plot scale using static flux chambers (SFC) have long informed the understanding of flux dynamics and have largely been the basis of global flux estimates. However, in many parts of the world, the landscapes where agricultural fluxes are generated come from larger fields. Eddy covariance (EC) can measure trace gases on larger fields, but there are few studies available quantifying CH4 emissions under typical practices at a field scale. Furthermore, few of these studies are from the U.S. Midsouth, the largest producer of U.S. rice. This study compares and quantifies field‐scale SFC and EC flux measurements on a large commercial system in northeastern Arkansas during the 2015 and 2016 growing seasons, following typical producer practices. Daily measured SFC CH4 fluxes did not differ from EC‐daily CH4 fluxes (p = .108). Total season CH4 emissions, calculated as the sum of daily fluxes ranged from 50 to 156 kg CH4 ha−1 season−1, with SFC reporting greater emissions than EC. Although SFC and EC‐daily flux measurements were similar early (p = .382) and late (p = .543) in the season, they differed mid‐season (p < .001) with SFC consistently reporting greater fluxes than EC. The findings of this study help unify season long plot‐scale and field‐scale flux measurements and signify an advancement of our understanding of GHG fluxes from rice systems. [ABSTRACT FROM AUTHOR]

The response of the mutual deliquescence relative humidity (MDRH) of several mixed salt systems to changes in mole ratio is presented here. The MDRH values of NH4Cl-NaCl, NH4Cl-(NH4)2SO4, and, for the first time, the NaCl-NaBr systems were acquired as a function of mole ratio. These changes were studied using attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. The MDRH values of 1:1 salt mixtures were consistently found to be lower than the values of the individual deliquescence relative humidity (iDRH) of NH4Cl-NaCl and NH4Cl-(NH4)2SO4. The exception was the MDRH of the NaCl-NaBr system, which was found to be higher than the iDRH of NaBr particles, but lower than the iDRH of NaCl particles. When the mole ratio of the mixed system was varied, the MDRH of the mixtures showed a slight dependence on the mole ratio. [ABSTRACT FROM AUTHOR]