Sweatin’ to the Coldies

Contributor
National Weather Service/NOAA
Type Category
Instructional Materials
Types
Model , Activity
Note
This resource, vetted by NSTA curators, is provided to teachers along with suggested modifications to make it more in line with the vision of the NGSS. While not considered to be “fully aligned,” the resources and expert recommendations provide teachers with concrete examples and expert guidance using the EQuIP rubric to adapted existing resources. Read more here.

Reviews

Description

Students add ice to a glass/jar of water. Students will observe water beginning to form on the outside of the glass/jar.

Intended Audience

Educator
Educational Level
  • Grade 8
  • Grade 7
  • Grade 6
  • Middle School
Language
English
Access Restrictions

Free access - The right to view and/or download material without financial, registration, or excessive advertising barriers.

Performance Expectations

MS-ESS2-4 Develop a model to describe the cycling of water through Earth's systems driven by energy from the sun and the force of gravity.

Clarification Statement: Emphasis is on the ways water changes its state as it moves through the multiple pathways of the hydrologic cycle. Examples of models can be conceptual or physical.

Assessment Boundary: A quantitative understanding of the latent heats of vaporization and fusion is not assessed.

This resource appears to be designed to build towards this performance expectation, though the resource developer has not explicitly stated so.

Comments about Including the Performance Expectation
This activity provides understanding of one part of the water cycle – condensation. This activity should be one of several that a student engages in. Other activities should include precipitation, evaporation, runoff, etc. When doing this activity a jar with a lid would be best. Students need to think about what is happening to the water molecules. Ask questions such as where does the water come from? Hopefully they say from the air but students may have the misconception that the water comes from inside the glass jar. If students say from the jar ask how it gets from the inside to the outside. If they are still having trouble dry off the jar, place in a dish and find its mass. Then after condensation has occurred find its mass again. If the water came from inside the jar then the masses should be the same or a little less (if some evaporates), but students will find that there has been an increase in mass because the water was “added” to the jar. The model doesn’t really go much further than condensation but after students determine the water came from the air they should begin thinking about the energy change that occurs for this to happen, which this activity doesn’t really go into. Students should already know about phase changes so ask, “Why does water evaporate? What causes water to condense or become a liquid again?” Students should draw and explain how the water vapor in the air ended up becoming liquid water on the jar. There is a change in the energy of the water (transfer of the energy of the water molecules in the air to the slower moving molecules in the jar and the water it contains) causing the molecules in the air to slow enough to become water droplets on the side of the glass. When enough condensation has formed on the jar, the water will slide down the jar due to gravity. Questions/discussion about how this activity relates to cloud formation and eventually rain should also be included so students can start relating this process to part of the water cycle. Students are not developing a model for condensation; rather, they are replicating an already established model. However if students are asked to draw and describe what is happening to the water molecules for condensation to occur they would be developing a model. Teachers may want to have students tweak the demonstration in order to discern the importance of the cold water. What happens if room temperature water is used? What happens if the water is heated? What may not be clear to students is that the water doesn’t have to be at 0oC. A metal can could be used (after being sure they understand the water doesn’t come from the container). Slowly add ice to the can letting it melt each time. Measure the temperature of the container with a laser thermometer. Continue the process until condensation begins to form on the container.

Science and Engineering Practices

This resource is explicitly designed to build towards this science and engineering practice.

Comments about Including the Science and Engineering Practice
This model shows that condensation will occur on cool surfaces. Students should take this model and develop a model (drawing) that more fully explains the processes that occur with the water molecules that leads to condensation. The model should indicate how the water vapor in the atmosphere transfers energy to the glass/object and the water inside the glass. (The ice will eventually melt and the water in the glass will begin to warm.) This process slows the water molecules in the air enough to become a liquid. The model should then be able to help them answer questions such where did the water come from? How cold does it need to be? Would it have to be the same temperature in a room someone had just taken a shower? Why or why not?

Disciplinary Core Ideas

This resource appears to be designed to build towards this disciplinary core idea, though the resource developer has not explicitly stated so.

Comments about Including the Disciplinary Core Idea
This activity focuses on condensation but can also lead to a discussion of precipitation by linking it to what happens in the atmosphere to form clouds which are composed of very small water droplets. When enough of those water droplets gather together (like when enough water condenses on the side of the glass) they begin to fall due to gravity. Other activities would be needed to address the other aspects of the water cycle (transpiration, evaporation, precipitation, and runoff) in order to fully address this disciplinary core idea and then pulling them all together to develop a full understanding of the water cycle.

Crosscutting Concepts

This resource appears to be designed to build towards this crosscutting concept, though the resource developer has not explicitly stated so.

Comments about Including the Crosscutting Concept
While the activity discusses how the lowering of the temperature of the water vapor molecules that come into contact with the jar causes them to condense on the glass it does not discuss it in terms of energy transfer. This transfer of energy is what drives the process of condensation. As mentioned before a discussion about phase changes and what causes them to occur could help in the understanding of what energy changes occur to cause condensation in this model. Students should be asked to explain what has to happen to the water vapor molecules in order for condensation to occur. They should be able to explain that the temperature of the water vapor molecules changes because energy is transferred to the jar and the water vapor molecules begin to move more slowly (their temperature decreases). When the molecules slow enough they become a liquid on the surface of the jar. This then needs to be related to the process in the atmosphere where water vapor molecules lose energy to the other molecules in the air and at some point move slowly enough to condense on condensation nuclei to form clouds. When enough of these molecules collide with each other they become heavy enough to be pulled down by gravity forming precipitation.

Resource Quality

  • Alignment to the Dimensions of the NGSS: As written is doesn’t fully support all 3 dimensions but additions can easily be included to provide more 3-dimensional learning. The activity does not completely support the disciplinary core idea because it has students working with just one aspect of the water cycle, condensation. It does have students using a model for this one part of the hydrologic cycle so it does involve parts of 2 dimensions: developing and using models and the roles of water in Earth’s surface processes. The crosscutting concept about energy is vague and would need to be expanded upon in order to more fully meet the 3-dimensions. To do this, students should create a model (a drawing) showing what is happening to the water molecules as they transfer their energy and slow enough to change from a gas (water vapor) to a liquid (the condensation). The alignment to NGSS becomes stronger as students do several activities that build their understanding of the hydrologic cycle.

  • Instructional Supports: The activity is simple and supports understanding of phenomena by using a visual model. It does engage students in a meaningful activity that helps students make sense of phenomena but it does not provide suggestions to help students understand what is actually happening as water condenses. As previously suggested students need to draw a model to really tie in the 3-dimensions and discuss their ideas with their peers. The instructional supports are very limited. It does not provide any suggestions of how to guide students through the activity and it does not provide ideas for differentiated instruction.

  • Monitoring Student Progress: This aspect is weak. There are no clear instructions on how to determine whether students are progressing or if they have a clear understanding of the concepts involved. Students often have the misconception that the water comes from inside the glass/jar and although the activity suggests asking students where the water comes from, it has no suggestions as to what to do if they answer incorrectly – “the water comes from inside the glass.” One way to address the misunderstanding is to draw a line on the container and cover it. Water from the condensation could then be collected and students could compare and observe that the water level does not change bringing it back to the question of, “where does the water come from.” Another idea as previously suggested is to find the mass of the jar as it sits in a dish and then find the mass again after condensation has been occurring. Having students create a model of what is occurring as the water molecules transfer their energy, slow and eventually become a liquid would also be valuable in determining if students are making sense of the process. Assessments would need to be created by the instructor.

  • Quality of Technological Interactivity: This resource has no technological component.