Earth & Environmental Sciences

Sunlight Intensity and the Albedo Effect

February 13, 2015

In the environment, light intensity and temperature are related. However, due to the reflective properties of different surfaces on the Earth (called the albedo effect), the degree that light intensity and temperature are related varies. This phenomenon can impact microclimates and weather patterns, which alters the habitat for plant and animal species. The choice of materials for building and landscaping in human-altered environments can mitigate or exacerbate this effect.

In this activity, students explore how solar energy is absorbed by surfaces and re-radiated as heat into the atmosphere. Using light and temperature sensors, students study the lag time between the highest light intensity and the highest temperatures in a single day and compare the thermal radiation of different surfaces. In the example below two fast response temperature sensors and a light level sensor were used. One fast response temperature (y1 - green) was placed on a grassy lawn, the second (y2 - purple) was placed on poured concrete nearby. The locations sun exposure was then monitored with the light level sensor (y3 - teal). The area received a mix of  direct and indirect sunlight throughout the day. 

temperature and light level data

Data collected from sunup to sundown. Students can compare sunlight intensity to temperature throughout the day. In this example, a temperature sensor was placed on cement and another was placed on a lawn to compare the albedo with the same light exposure. 

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