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SAM E1 Model 1
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Forces on Atoms
Did you know that there are forces between all atoms?
Before getting into the details of these forces, use this model to get a "feel" for the forces between atoms.
Find out how close atoms need to be for there to be attractive forces.
Atoms respond to forces just like balls, boats, and beetles. Newton's Laws apply just as much to them.
What you need to know:
This is a model of two atoms in a box.
The black arrows show the force on each atom.
You can move the atoms around and see the forces on each.
You can set the atoms anywhere and then run the model.
Note:
If you overlap the atoms much, the forces are too large. Atoms cannot overlap.
The model will generate an error message if the forces are too large.
Challenges:
By looking at the forces, can you predict how the atoms will move when you start the model from rest?
Can you set the atoms' locations so that when the model is started, the atoms are close but move very little?
Do you wonder what causes these forces? [Hyperlink to force page]
Now, let's take a deeper look at this force and how it depends on the separation between atoms.
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<head>
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<body>
Do this:
<p>
Click on an atom and move it around. Observe the forces.
</p>
<p>
Start the atoms (from rest) and observe their motion. Where do they go
fast, slow, and stop?
</p>
<p>
Use the "Simulation speed" slider to slow down the motion to follow what
happens when the atoms are close.
</p>
<p>
Use the "High Speed Start" to give the balls more energy.
</p>
</body>
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<html><b><font size=3>Start from Rest</html>
Run the model starting with zero velocity
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<html><font size=3><b>Stop</html>
Stop the model
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<html><b><font size=3>Continue</html>
Resume the model calculations
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<html><b><font size=3>High Speed Start</html>
Start the balls moving quickly
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<html>
What do you observe about the forces between atoms?
Make a list of at least four different properties of these forces.
</html>
1. The force on one atom is always equal in magnitude to the force on the other.
2. The force is always directly toward or away from the other atom.
3. There is no force if the atoms are far apart.
4. The force is attractive until the atoms get close and then repulsive.
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Hint 1
Get a hint
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At any one time, how are the forces on the two atoms related?
Hint
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Hint 2
Get another hint
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How do the forces change with distance?
Hint
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