UTF-8SAM E1 Model 1255255192
The last activity showed that if you left a few atoms alone, their total energy will be constant. Will this be true for billions of atoms?
Well, we cannot model billions, but we can see what happens with up to 500 atoms.
Here is a model with 100 atoms. Does it conserve energy? What about a model with more atoms?
The model has some buttons that you can use to answer this question.
The third button above the model allows you to add many atoms into any empty space on the model.
The fifth button above the model is a counter. Drag it over a rectandular area and it will tell you how many atoms are there.
The buttons below the model add and subtract a bit of kinetic energy from all the atoms.
The new atoms start at rest, so you may want to speed them up by using the "Add KE" button.
Red: KE per atom
Blue: PE per atom
Green: Total energy per atom
The model you have been using is very powerful. But it isn't perfect. In the final activity, we will explore its limitations.
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<b><font size="5" face="Trebuchet MS">Energy Conservations with MANY atoms</font></b>
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Page 9 of 11
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</html>-243f9a7575Trebuchet MS180.080.01414true1480.01440.080.0true100.0100.0100.0true100.0truetrue100.01org.concord.mw2d.activity.AtomContainerpage9$0.mmlfalseorg.concord.modeler.PageXYGraph0Time (fs)Kinetic Energy/ParticlePotential Energy/ParticleTotal Energy/Particlefalse0.050000.0false-0.20.2400350Time (fs)Energy (eV)true320450-333301-1falseRaised Bevelorg.concord.modeler.PageButtonAdd KESpeed up every atom11836falseorg.concord.mw2d.models.MolecularModel0Heat the system up0.01org.concord.modeler.PageButtonSubtract KESlow every atom down a bitfalseorg.concord.mw2d.models.MolecularModel0Cool the system down-0.0140.0100.0org.concord.modeler.PageTextArea400200<html>
As long as you leave them alone, what happens to the total energy of 100 and 500 atoms?
</html>You can change the total energy by adding and subtracting KE, but unless you do, the total energy stays constant no matter how many atoms you use. 100.0100.0true40.040.01truetruepage8.cmltruetrueindex.cmltruetruepage10.cmltrue