Two Atoms in a Box (collisions and transfer of energy)

Interactive, scaffolded model

Overview and Learning Objectives

Students observe and measure the interaction between two atoms. By observing the change in kinetic energy when atoms collide and analyzing a graph of their kinetic energy, students learn that total kinetic energy is conserved.

Students will be able to:

• predict what will happen to the kinetic energy of two atoms before and after a collision;
• apply the rule of energy conservation to explain what happens when something seems to "lose" energy.

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Assessment

Imagine you are at a party where someone dared you to pop one of the helium ballons in a room that has all the windows and doors closed. Describe what would happen to those Helium atoms once they have been released from the balloon. Specifically talk about their eventual position inside the room and what their kinetic energies would be like if you could actually measure them.

You have a box of gas in which, at some instant, all the molecules have the same kinetic energy. What do you think will happen?

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Classroom Practice

http://www.concord.org/~barbara/workbench_web/unit1/1-06TwoAtomsInABox.html

This activity is one from a longer unit, Atoms in Motion, which begins at:

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

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Central Concepts

Key Concept:

Collisions between two atoms result in a transfer of kinetic energy (energy of motion) from one atom to the other, and demonstrate that the total kinetic energy of the two atoms is the same before and after the collision.

Additional Related Concepts

Physics/Chemistry

• Collision
• Energy
• Energy conservation
• Energy transfer

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Textbook References

• Biology: Exploring Life - Chapter 4: The Chemical Basis of Life
• BSCS Blue (8th Edition) - Chapter 2: Energy, Life and the Biosphere
• BSCS Human - Chapter 8: The Cellular Basis of Activity
• Web of Life - Chapter 4: Photosynthesis and Cellular Respiration

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Benchmarks and Standards

AAAS

• COMMON THEMES: Constancy and Change - Graphs and equations are useful (and often equivalent) ways for depicting and analyzing patterns of change (Full Text of Standard)
  
  
• COMMON THEMES: Constancy and Change - Things can change in detail but remain the same in general (the players change, but the team remains; cells are replaced, but the organism remains) (Full Text of Standard)
  
  
• THE PHYSICAL SETTING: ENERGY TRANSFORMATIONS - When energy of an isolated atom or molecule changes, it does so in a definite jump from one value to another, with no possible values in between (Full Text of Standard)
  
  
• THE PHYSICAL SETTING: MOTION - The change in motion of an object is proportional to the applied force and inversely proportional to the mass (Full Text of Standard)
  
  

NSES

• Physical-Science: Energy Conservation / Entropy - 1 The total energy of the universe is constant (Full Text of Standard)
  
  
• Physical-Science: Energy Conservation / Entropy - 2 All energy can be considered to be either kinetic energy, which is the energy of motion; potential energy, which depends on relative position; or energy contained by a field, such as electromagnetic wave (Full Text of Standard)
  
  
• Physical-Science: Motions and Forces - 1 Objects change their motion only when a net force is applied (Full Text of Standard)
  
  

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Macro Micro Link

When playing pool, some or all of the energy of the cue ball is transferred to the ball being hit.

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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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