In case you missed it, last month, was all about the 2017 International Virtual Science Symposium. There were over 140 entries from all 6 GLOBE regions. Students submitted reports about their research on all of the “spheres” (hydrosphere, atmosphere, biosphere, pedosphere, and earth as a system) and they were reviewed by a panel of scientists, teachers, and science enthusiasts to be rewarded with stars and badges.
I had the wonderful privilege of being able to read through and review several projects. I was blown away with the thought and hard work that went into these projects. Of course, being an amateur scientist, I couldn’t help but notice “trends” in the reports. Looking just at the titles of projects, I saw that temperature was one of the most commonly measured thing. It was mentioned in 25 of the titles and likely a significant part of the data measured in many more. While that includes water, soil, and atmospheric temperature, 7 projects looked at surface temperature in particular (there were more than just 7 projects that included surface temperature in their data, but there were only 7 that included the phrase “surface temperature” in the title).
The other day, as I was staring out my office window at the GLOBE Implementation Office in Boulder, Colorado, USA, watching the clouds roll in from over the mountains bringing a much appreciated string of cooler weather to break up the 90-100 degree F (32-37 degree C) heat wave we had been experiencing for the past week, I started thinking about the student reports on surface temperature. As hot as it was in Boulder, Arizona, which is southwest of Colorado, was experiencing a record setting heat wave that caused temperatures to stay above 110 degrees F (43 deg C) for 7 consecutive days (yikes!). In addition to planes not being able to fly, people being able to bake cookies on their car’s dashboards, and trash cans melting, people were told to keep their dogs indoors because their paws were burning up (double yikes!). I immediately thought of my dog, an adorable and fluffy golden retriever named Buddy Guy. I wondered, much like the students in Akron, Ohio who submitted several reports on surface temperature around their school, about the surface temperature of the asphalt. I like to take Buddy on walks, and luckily for him I typically take him out later in the day when the air has cooled down a bit. Though now I worried if the asphalt cooled down as much as the air or was I still putting his paws at risk. I decided to do some research. Since I also walk him on concrete sidewalks and grass, I wanted to include data on those as well. My research question was: how does the change in the surface temperature of asphalt compare to concrete and grass from day to night? I hypothesized that asphalt would have the highest surface temperature, concrete would be in the middle, and grass would have the lowest surface temperature. This is because asphalt is the darkest in color. Darker colors absorb more heat than lighter colors. Even though the concrete was the lightest surface, I thought the grass would still have the lowest surface temperature during the day because it is being cooled by evapotranspiration. My other hypothesis was that at night, all three surfaces would see a drop in surface temperature but the surface temperature of asphalt would remain higher than concrete and grass because it would retain some of the heat that it absorbed during the day.
I chose a site that had asphalt, concrete, and grass close by. After defining my site in the GLOBE Data Entry App, which was very easy and gave me my coordinates and altitude, I collected 5 surface temperature measurements approximately 10 meters apart using a hand-held infrared thermometer. I repeated the process on a concrete sidewalk and on a grassy area. Since there was less grass, I only spaced my measurements 5 meters apart. I recorded the air temperature data I got using an alcohol filled thermometer and the sky conditions in the Data Entry app. The app made it easy because it walked me through each step with very clear directions and pictures to help me with my sky observations. I repeated the process at night and then 2 more days in a row, gathering data at around 14:00 (2pm) (around the hottest time of the day) and around 21:00 (9pm) (shortly after the sun set). Side note: I usually walk Buddy during dusk, before the sun sets, but for the sake of this experiment I chose to test after dark. An ideal experiment would be to take surface temperature measurements once every hour for a few days to get a real sense of the change in surface temperature over time, but who has time for that?!