Drexel-SDP GK-12 Activity

Creating a Model of the Water Cycle Subject Area(s) Science Associated Unit None Associated Lesson None Activity Title Creating a Model of the Water Cycle

Grade Level 7 (5 - 8) Time Required 1.5 hrs Expendable Cost per Group $5

Summary This activity allows students to create models of the earth’s water cycle. Their goal is to use inquiry-based activities to model their knowledge of the water cycle. They experiment with different materials and structures to determine how they can replicate the earth’s natural environment.

Engineering Connection Engineers study and solve problems on a variety of scales, large and small. For example, with nanotechnology engineers solve problems on materials too small to be viewed by the naked eye and aerospace engineering often solve problems involving the scale of the universe. In either case engineers cannot conduct experiments directly on their studied topics. Therefore they create models on which they can experiment.

Engineering Category Relates science concepts to engineering.

Keywords Water Cycle, Evaporation, Condensation, Precipitation

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Educational Standards • Pennsylvania Science: 3.4 Physical Science, Chemistry, and Physics

Pre-Requisite Knowledge Prior knowledge of the Water Cycle, not required but helpful

Learning Objectives After this lesson, students should be able to: • Understand how the water cycle works

Materials List Each group needs:

• Plastic container with a lid that can be closed • Sand • Clay • Moss • Newspaper • Water • Plastic wrap

Introduction / Motivation Engineers try to solve problems on real life materials that can be very big or very small. For example, when civil engineers want to figure out which one of two bridge designs would be better they can not feasibly build both large bridges. This could take too much money and time especially if one would eventually be torn down. Instead they build smaller models that allow them to see what they are looking for. The use of models allows engineers to try things and experiment with objects that are either too large or small to experiment in their actual size.

Vocabulary / Definitions Word Definition

Model A miniature or large representation of something Precipitation A deposit on the earth of hail, mist, rain, sleet, or snow. Condensation The conversion of a substance (water) from the vapor state to the liquid state. Evaporation The conversion of a substance (water) from the liquid state to the vapor state.

Procedure

1) Review, or teach, the water cycle to students.

2) Provide students with a list of materials, the plastic container, clay, sand, moss, water, and plastic wrap.

3) Ask students how these materials can relate to the water cycle.

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4) Allow students to create drawings of how they can use these materials to model the water cycle.

5) After approving of their designs allow them an opportunity to create their models. 6) Once the models are complete place a sheet of plastic wrap over the top prior to closing

the lid. 7) Place the models in a place where they will not be disturbed. 8) For several days ask students to make observations about the changes in their model.

Lesson Closure Once condensation appears on the lid ask students to explain why this is occurring. Ask students to explain how this processes is similar the earth’s water cycle.

Troubleshooting Tips The amount of time before students will observe the evaporation and condensation cycle depends on climate when you do this activity. If the containers are stored in a cool, even temperature, location the process may take up to a week. For quicker results place the containers near a window and/or other heating/cooling source such as a heater.

Assessment Activity-Embedded Assessment: While the students are designing their model, prior to building it, you can see if the students understand the water cycle. Students should be able to explain why they need a lid to create a closed system and having a place for the condensation to collect. They should also design a holding space for there to be a water source. Post-Activity Assessment: Once the condensation can be observed ask students to explain where it comes from and what happens to the liquid once it falls. They should describe the evaporation process, liquid to vapor, and then condensation, vapor to liquid. They should also compare the falling condensation to precipitation.

Owner Drexel University GK-12 Program Contributors Quincy Brown, Jason Henderson Copyright Copyright 2009 Drexel University GK12 Program. Reproduction permission is granted for non-profit educational use