Look for: Person A (seeing sunrise) is seeing a dimmer,…

9.A Revise our Earth–Sun system model to include ideas about how the Earth’s atmosphere causes light from the Sun and Moon to change colors.

As students talk with their partners and then again during the upcoming discussion, listen for students to share ideas such as these:

• Person A (seeing sunrise) is seeing a dimmer, reddish-orange-colored Sun because the light is passing through more of the atmosphere.
• Person B (midday) is seeing a brighter yellower/whitish Sun because the light is passing through less of the atmosphere.
• Materials in the atmosphere (such as water vapor, clouds of water droplets and ice, other gasses, dust, and pollution) are affecting the color of light from the Sun–the more atmosphere the light travels through (such as for Person A), the more effect (more color change) we see.

Other differences in the atmosphere (more pollution in some places than others, for instance) could also affect how people see the Sun from their position

If students need more support in determining the different “amounts of atmosphere” the sunlight travels through to reach Person A and Person B, encourage them to use a ruler and/or protractor to actually measure the lengths and/or angles of the sunlight approaching Person A and Person B to help them contrast those positions.

Refer back to the images we used earlier in the lesson to clarify with students what each person would be seeing; you might even print out and attach small photos of the sky at sunrise near Person A and the Sun in the sky at noon near Person B to help students associate the view each person would have of the Sun and the different colors they might see.

Take note of which students may need support during the sharing discussion that follows this partner talk; consider checking in with them before the whole-group sharing to alert them that you’ll be asking their help measuring for the class, annotating the model, or restating what someone else said in their own words.

Discuss why we might see different colors in the sky at different times of day. Display slide R. Use prompts such as those shown here to have students share their ideas of possible causes for the color changes we’ve noticed.

Suggested prompts

Sample student responses

Follow-up questions

What variables did you or your partner identify that might be causing the differences we see in the sky between noon and sunset?

Maybe the angle of the incoming light

Why might that be important?

Could we measure that?

If there’s different stuff in the atmosphere

What would cause there to be different stuff in the atmosphere?

Do you mean at different times and/or different places?

How far the light travels through the atmosphere

How did you notice that?

Could we measure that?