UTF-8Brownian Motion: Discovering the Cause of Brownian Motionyellow_fabric.gifBrownian Motion: Discovering the Cause of Brownian Motion
Observing the Motion of One Atom
Brown's observation of a tiny particle moving in a random pattern when floating in water was considered to be a historic event. For 2000 years people speculated that atoms existed. Until Brown, nobody had any visual evidence that everything was made of atoms (and molecules, which are groups of bonded atoms). To understand why Brown's observations helped give us insight into the atomic nature of all matter, we need to understand how an individual atom behaves.
Below is a model which contains only one atom, nothing else.
Experiment with giving the atom an initial velocity, and then run the model to see how it behaves.
To change the velocity of the particle click on the button above, then click on the atom, and drag the tip of the yellow velocity arrow.
To run the model press the button above.
To reset the model press the button above.
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<strong><font face="Times New Roman, Times, serif" size="4">Describe the
motion of a single atom. How is this different from the motion that Brown
observed of a particle in water?</font></strong>
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<strong><font face="Times New Roman, Times, serif" size="4">Brown found
the strange movement of tiny particles so fascinating that he stared at
them for hours. They never stopped bouncing around. Assuming the motion of
the particles he saw was due to water being made from atoms (or
molecules), what do you notice about the atom above that would help to
explain his continual observation of particle movement?</font></strong>
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