This activity is related to a Teachable Moment from Aug. 10, 2017. See " Get Students Excited About Science With This Month’s Total Solar Eclipse. "

Overview Students find the Sun’s location in the sky for different points in time during an eclipse. They will then use mobile devices to measure lux before and during the eclipse to examine the impact a solar eclipse has on the energy received at Earth’s surface.



Background

Solar energy is radiant energy that is produced by the Sun. Every day, the Sun radiates an enormous amount of energy. The amount of solar energy a place on Earth receives depends on several conditions. Mostly, it depends on latitude (as it relates to the season of the year, the angle of the Sun, and the amount of daylight hours), but it also depends on the clearness or cloudiness of the sky.

Like clouds, a solar eclipse, whether total or partial, will block sunlight and reduce the amount of solar energy that reaches the ground.

The amount of light that falls over a given area is measured in lux (equal to one lumen per square meter) and can be measured using the light sensor on a mobile device. By measuring lux during an eclipse, students can compare the reading to measurements taken of the full sun to see what impact a solar eclipse has on the amount of solar energy received on Earth.