## Item CL105002: Sunlight is most intense at a place on a day when the sunlight strikes that place at a 90° angle.

The two diagrams below show the earth on two different days of the year. The arrow indicates the place where a student lives.

Assuming that the sky above her is cloudless on both days shown above, on which day is sunlight more intense where she lives?

1. Day 1 because the more the North Pole is angled toward the sun, the more intensely the sunlight strikes everywhere in the northern hemisphere.
2. Day 2 because sunlight strikes where she lives at a 90° angle, and sunlight is most intense where it strikes the earth at a 90° angle.
3. The intensity would be the same where she lives on both days shown in the diagrams because intensity of sunlight only depends on how far north or south a place is.
4. How much the North Pole is angled toward the sun does not affect how intense the sunlight is where she lives. Sunlight has the same intensity where she lives on both days.

Distribution of Responses

Percent of students responding correctly

 Overall 43% Grades 6–8 40% Grades 9–12 47% Male 43% Female 44% Primary Language is English 44% Primary Language is not English 38%