Look for: Changes in the amount of daylight and angle o…

3.B Collect and produce data showing patterns of changes in daylight and the angle of elevation of the Sun in the sky to serve as evidence to evaluate the accuracy of an initial physical Earth–Sun System model.

Students collect data using NOAA websites to identify patterns of changes in daylight and the angle of elevation of the Sun in the sky over hundreds of years. Look for the following:

Changes in the amount of daylight and angle of elevation of the Sun in the sky occur in a cyclical pattern, repeating over hundreds of years.

The concept that this is a repeated, cyclical pattern is important to establish so that students can use this data as evidence to examine the accuracy of the physical models created later in the lesson. If students are struggling to identify the patterns in the data because of how the data is structured by years, encourage them to re-write the data by months to make the yearly patterns more visible.

Lead a building understanding discussion. Present slide K.

Suggested prompt

Sample student response

How has the amount of daylight changed over 500 years?

It stayed the same or only changed by a couple of minutes.

over 1,000 years?

It stayed the same or only changed by a couple of minutes.

over 1,500 years?

It stayed the same or only changed by a couple of minutes.

How has the solar elevation changed over 500 years?

They were pretty close.

They changed by hundredths of degrees.

over 1,000 years?

• Some stayed the same, but others changed.
• Some changed by hundredths of degrees, and others changed by tenths of degrees.

over 1,500 years?

They changed by tenths of degrees.

What’s the relationship between the solar elevation and amount of daylight over the hundreds of years?

The higher the Sun is in the sky, the more daylight we have, so the Sun is taking a longer time to pass across the sky as it’s going higher.

How does this compare to the data you recorded using the videos of the simulation?

• The data from the websites matches the data we recorded when we measured solar elevation and length of daylight from the simulation.
• The data is not exactly the same, but the patterns are the same.

How does this data help explain why or how different communities created rituals to help mark and predict changes in the patterns of daylight during a year?

• The changes in the Sun are stable and predictable.
• These changes follow a stable pattern over hundreds of years. So people could count on the same things happening with the Sun at the same time each year.