Attractive Forces and Phase Change: (Atoms in Motion)

Interactive, scaffolded model

Important Notice!

The activity will work properly on Windows and OS 10.4+ with Java 5.0 updates installed.

return to top

Overview and Learning Objectives

Class begins with a discussion about the necessity of changing the model to accommodate attractive forces between atoms and why this is needed to model phase changes. Students then use a computer model to visualize phase changes and understand boiling points.

Students will be able to:

• evaluate a model for deficiencies in describing observed phenomena;
• using a computer model, demonstrate what conditions are necessary to have low and high boiling points;
• interpret the relationship between strength of atomic attractions and boiling point;
• describe why liquids and solids form;
• describe what happens on an atomic level when a substance changes phases.

return to top

Assessment

Suppose you were a molecule in a liquid in a glass. Someone then takes that glass and puts it in the freezer. After a while the liquid freezes. How does what you see and feel change?

return to top

Classroom Practice

Teacher Guide: http://www.concord.org/~barbara/workbench_web/unit1/1-16PhaseChanges.html

This activity is one of a larger module, Atoms in Motion:

http://www.concord.org/~barbara/workbench_web/unit1/index.html

return to top

Central Concepts

Key Concept:

There is an attractive force between all atoms, causing or preventing phase changes and resulting in specific melting and boiling points.

Additional Related Concepts

Biology

• Ecosystems

Physics/Chemistry

• Distance between particles
• Evaporation
• Gas
• Hydrogen bonds
• Kinetic motion
• Liquid
• Melting point
• Molecular movement
• Phase change
• States of Matter

return to top

Textbook References

• Biology: Exploring Life - Chapter 34: The Biosphere
• BSCS Human - Chapter 9: The Cycling of Matter and the Flow of Energy in Communities

return to top

Extensions and Connections

This model also appears in the States of Matter module.

return to top

Macro Micro Link

Even on the nicest day, a hot air balloonist often encounters clouds. Clouds consist of many tiny liquid drops. This activity will help explain how and why liquids form.

return to top

Activity Credits

Created by CC Project: Molecular Workbench using Molecular Workbench + Pedagogica

return to top

Requirements

• Java 1.5+ - Java 1.5+ is available for Windows, Linux, and Mac OS X 10.4 and greater. If you are using Mac OS X 10.3, you can download MW Version 1.3 and explore within it instead.

return to top