Key Idea: As the earth moves around the sun over the course of a year, the orientation of earth’s axis with respect to the sun changes and the latitude of the place that is directly beneath the sun changes. This shift causes the intensity of energy from the sun that any place receives to change over the course of a year.

Students are expected to know that:

  1. As the earth moves around the sun over the course of a year, the orientation of earth’s axis relative to the sun changes, which gradually shifts the place on the earth where the sun is directly overhead (the sub-solar point). In late June the sub-solar point is at its northernmost location on the earth’s surface, 23.5° north of the equator (the northern border of the tropical region). From late June to late September it gradually moves toward, over, and then away from the equator until it reaches a point 23.5 degrees south of the equator in late December. Then it moves back toward and past the equator, reaching the equator in late March.
  2. The gradual north-south shift in the position of the sub-solar causes a gradual change in where the sunlight is most intense. Because the intensity of sunlight that reaches a place over a day decreases the farther north or south a place is from the latitude of the sub-solar point on that day, the greatest intensity of sunlight hitting the earth’s surface is in the northern hemisphere in late June and gradually shifts toward the southern hemisphere until late December, when it begins shifting north again.
Percent of students answering correctly (click on the item ID number to view the item and additional data)
Item ID
Number
Knowledge Being Assessed Grades
6–8
Grades
9–12
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CL117002

At a given place, the sun is higher in the sky in the middle of the day in summer than in winter because the orientation of the earth’s axis relative to the sun is different in summer than it is in winter.

36%

43%

CL114002

The sun passes directly overhead during the month of May at a place that is a little farther north of the equator than it passed over the day before.

32%

36%

CL116002

The intensity of sunlight striking the surface of the earth is always greater the closer a place is to where the sun passes directly overhead.

30%

36%

CL115002

The place where sunlight strikes the earth’s surface at a 90° angle during the months of May and October is a little farther north each day in May and a little farther south each day in October.

29%

37%

CL120002

The point on the surface of the earth where sunlight is most intense from June of one year until June of the next year shifts from 23.5° north of the equator to 23.5° south of the equator, then back to 23.5° north.

26%

34%

CL117001

At a given place, the sun is higher in the sky in the middle of the day in summer than in winter because that place is closer to where the sun is directly overhead in the summer than it is in the winter.

25%

25%

CL119002

For a place where the sun is directly overhead in the middle of the day in late December, the sun would not pass directly overhead at any time in February.

17%

17%

Frequency of selecting a misconception

Misconception
ID Number

Student Misconception

Grades
6–8

Grades
9–12

CLM082

The intensity of sunlight striking the surface of the earth is always greater the closer a place is to the equator (AAAS Project 2061, n.d.).

37%

37%

CLM083

The point on the surface of the earth where sunlight is most intense is always at the equator (AAAS Project 2061, n.d.).

29%

28%

Frequency of selecting a misconception was calculated by dividing the total number of times a misconception was chosen by the number of times it could have been chosen, averaged over the number of students answering the questions within this particular idea.