Phase Change

Interactive, scaffolded model

Important Notice!

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

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Overview and Learning Objectives

Students view a computer model of molecules in a solid, a liquid, and a gas and then discuss how this model helps describe the macroscopic properties of each state

Students will be able to:

• Diagram the atomic level structure of a solid, liquid, and gas;
• Describe the state of motion of atoms in a solid, liquid, and gas;
• Predict if a substance is compressible or not;
• Compare the macroscopic characteristics with microscopic characteristics for the three phases.

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Assessment

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

Could there be a compressible liquid? Explain your answer using molecules/atoms in your answer.

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Central Concepts

Key Concept:

The compressibility of a substance indicates the space, or lack of it, between the atoms or molecules of various states of matter.

Additional Related Concepts

Concept Map Available

Physics/Chemistry

• Compression
• Gas
• Liquid
• Solid
• States of Matter

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Textbook References

• Biology (Miller and Levine) Prentice Hall 5th Edition - Unit I: Chapter 3 - Introduction to Chemistry
• Biology: Exploring Life - Chapter 4: The Chemical Basis of Life
• BSCS Blue (8th Edition) - Chapter 1: The Chemistry of Life
• Cell Biology (Pollard and Earnshaw) Saunders 2002 - Chapter Two: Molecular Structures
• Web of Life - Chapter 2: Chemical Basis of Life

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Benchmarks and Standards

AAAS

• THE PHYSICAL SETTING: FORCES OF NATURE - There are two kinds of charges-positive and negative. (Full Text of Standard)
  
  

NSES

• Physical-Science: Matter Structure/Properties - 5 Solids, liquids, and gases differ in the distances and angles between molecules (Full Text of Standard)
  
  

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Extensions and Connections

This activity also belongs to two different larger modules: Atoms in Motion

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

and

States of Matter

http://workbench.concord.org/web_content/states_of_matter/index.html

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Additional Info

Additional Background

From the AAAS Benchmarks:

1. THE PHYSICAL SETTING G. FORCES OF NATURE: At the atomic level, electric forces between oppositely charged electrons and protons hold atoms and molecules together and thus are involved in all chemical reactions. On a larger scale, these forces hold solid and liquid materials together and act between objects when they are in contact, as in sticking or sliding friction.

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Macro Micro Link

The larger unit Atoms in Motion makes the following macro-micro link: the hot air balloon is not just hot air. Without the fabric of the balloon to contain the hot air, it would not fly. Without being able to carry liquid fuel, a hot air balloon ride would be short. Students extend their studies to other states of matter.

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Activity Credits

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

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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.

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