Look for: Increased temperatures cause an increase in e…

3.B Modify a model - based on evidence - to match how a change in atmospheric temperature affects evaporation in Earth’s water system.

• Increased temperatures cause an increase in evaporation and more water vapor in the atmosphere.
• Students citing data from the bottle setups to support that this is a causal relationship.
• Students citing evidence from the NASA Water Temperature and Water Vapor visualization as additional evidence that increased temperatures cause more evaporation.
• Some students may bring their understanding of energy transfer from prior units to explain the causal relationship between increased temperature and increased evaporation.
• Students making suggestions for how to modify the model to show changes to evaporation (e.g., suggesting up arrows to show an increase) and changes in precipitation (e.g., suggesting that winds move water vapor in the atmosphere and where there may be more or less precipitation).

If students do not agree on the causal relationship between an increase in temperature and an increase in evaporation, transition to thought experiments around other explanations. For example:

Allow students to suggest other causes that would explain why there was more evaporation in the heated conditions. Use the prompt, If an increase in temperature is not causing more evaporation, what other variables or factors can we identify in our bottles that would explain why the heated conditions had more evaporation? Be prepared to test these new ideas.

• Have students track evidence from the bottle setups, visualizations, prior science learning, and out of school experiences that support that increased temperature causes increased evaporation. Chart evidence that supports or does not support this explanation.
• If students have prior learning of energy transfer, consider modeling at the particle scale the movement of particles in increased temperature scenarios, how those particles transfer their energy to water particles at the surface of Earth, and how water particles that gain enough kinetic energy to evaporate.
• If students struggle to suggest ideas for modifying the model, take a moment to suggest a few options for what could be represented and ask students which of those options best captures what they figured out and how they could communicate their new ideas to someone new to understanding these ideas.