Brownian Motion

[Doc_B]

Dear Fu-Kwun Hwang,

is it possible to create the brownian path in 3 Dimensions?

I just tried to do it, but it was not very successful.

Maybe anybody can help.

Thanks in advance ...Thorsten.

[Fu-Kwun Hwang]

It is possible to create the brownian path in 3 Dimensions.
However, you need to process 3D collision.
Please check out Collision 2D

[claudiahenry]

Very nice Site number one topic Thanks you..

[khayx]

First of all, thank you very much for this fantastic site!

I would like to create the following system; if there is someone willing to help, I will gladly give co-authorship of an upcoming paper on the subject.

The systems consists of a set of smaller particles (with the option to vary their masses and the energy of the system) to create the brownian environment and two other kinds of particles (with the option to vary their masses):
1. particles which stick to each other on contact and
2. particles which do not stick to each other on contact.
There should be a counter for each time a couple of this particles touches each other, and another counter for each time the sticky particles stick to each other.
When there is collision of any of these two kinds of particles, the system stops and scrambles the position of all particles but the counters do not initialize. The purpose is to count and compare the interaction of these two distinct sets of particles.

I hope someone is interested.
Many thanks in advance

[Fu-Kwun Hwang]

How many particles for each kind of particles you would like to simulate?
And what are the size of each kind of particles (or ratio of radius between two particles?)?
What are the average kinetic energy of each kind of particles (the same average kinetic energy or the same average velocity?)

When there is collision of any of these two kinds of particles, the system stops and scrambles the position of all particles but the counters do not initialize.

If there are too many particles , collision between two particles will occurs very shortly.
Do you really want to scrambles the position of all particles

[KateDaring52]

Well, great work! You have helped me to improve my knowledge about this field. Thank you so much for sharing.

-*-

[khayx]

Dear Prof. Hwang,

Thank you very much for replying to my post.
The total number of particles could be variable.
The ratio of radius between the two particles could also be variable.
I would prefer the particles to have the same average kinetic energy.

[Fu-Kwun Hwang]

particles which stick to each other on contact

For those particles which would stick to each other, what need to be modeled when they stick together?
It is a inelastic collision: momentum is conserved but energy is not conserved.

How about angular momentum? Will it rotate around their center of mass?
Or two particles become one bigger particles (with twice the mass and larger radius)?
What will happened when the third particle contact with those two particles?

I need a model in order to create simulation (which is suit to what you really want).
Please provide more detail information so that I can understand what you might want.

I have another question: suppose there are two kind of particles A and B.
Do you mean if A collide with A or B collide with B , they will stick together;
Particle will not stick with each other if A collide with B?

[khayx]

I want to study if particles that have some sort of affinity for each other (they stick together when they touch) collide more often than particles that don't have any affinity. I know this sounds crazy and not logical, but the truth is to be observed. The system should not be too sophisticated.
Now that you have forced me to reflect on the model, I think it would be better not to interrupt the particle movement of the whole system after the sticky particles or the non-sticky particles touch. Summarizing:
1- There is a bulk of small particles that account for the Brownian system, the sticky particles and the non-sticky particles.
2- Particles have the same average kinetic energy.
3- There are no energy losses (heat).
4- When particles stick together, it could be due to a force that only acts when they interact.
5- This force is discrete, constant, originates in the point where they touch each other and points towards the centre of the particles; it would be interesting to make this force a variable as well.
6- When particles stick together they rotate, there is a angular moment around their centre of mass.
7- When the kinetic energy of the other colliding particles plus the centrifugal force caused by their rotation around the centre of mass allows, the sticking particles separate.
8- There is a counter for each time the sticky particles touch (and stick together). Another counter for each time the non-sticky particles touch.

Thank you very much for your constructive critics and for all the time spent on this model.

[Fu-Kwun Hwang]

I want to study if particles that have some sort of affinity for each other (they stick together when they touch) collide more often than particles that don't have any affinity.

Are you trying to compare two different cases: in different system?
1. system A: particles which stick together when they touch.
2. system B: particles which collide with each other when they touch.

If there are two different kinds of particles A and B, then they are three different cases
1. A and A touch
2. B and B touch
3. A and B touch
It is more than two cases.

Model for the following simulation : There are two kind of particles A,B
When same kind of particle touch, they will stick together and become a bigger particle (momentum is conserved but energy is not conserved).
Elastic collision occurs when different kind of particle touch each other (energy and momentum are conserved).

The energy is not conserved if two particles stick together.
 

Embed a running copy of this simulation
<applet code='users.ntnu.fkh.browianmotion2type_pkg.browianmotion2typeApplet.class' archive='http://www.phy.ntnu.edu.tw/ntnujava/ejsuser/2/ejs_browianmotion2type.jar' name='browianmotion2type8403' id='browianmotion2type8403' width='540' height='595' mayscript=true><param name='draggable' value='true'></applet>
Embed a running copy link(show simulation in a popuped window)
<a href='http://www.phy.ntnu.edu.tw/ntnujava/msg.php?smfejs=8403' target='smfejs'>Run simulation</a>

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Press the Alt key and the left mouse button to drag the applet off the browser and onto the desktop. This work is licensed under a Creative Commons Attribution 2.5 Taiwan License

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• Post questions to be asked to help students to think, to explore.
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[khayx]

Thank you very much for this first (funny) approach.

1- When two blue particles touch, they should not become one bigger particle, but just stick together until the medium pulls them apart (the sticking force should be a variable). There should be a counter to record these events. (blue counter)

2- When two green particles touch, they just collide but they don’t stick together. There should be a counter to record these events. (green counter)

[Fu-Kwun Hwang]

The model has to be pre-defined when a simulation is created.
Please specify the nature  of sticking force. Is it a constant or is it depends on number of particles sticked together? or...

You only said when blue particles touch , they should stick together; when green particles touch, they should collide with each other.
What will happened if blue particle touch green particle??? Ignore?

What need to be conserved when blue particles stick together? momentum and angular momentum?

What is the purpose for the simulation?

[khayx]

The force is constant and is not dependent on the number of particles interacting.
When blue particles touch green, the same happens as when green touch green: perfect elastic collision.
Ideally, total momentum (linear and angular) should be conserved. For the sake of simplicity, just consider linear and discard angular momentum.

The purpose of this lab would be to try to determine the statistics of these two kinds of interactions (the sticky and the non-sticky).

[dennisseda]

Hi,

I would like to embed the .jar file into my website as part of a quick reference guide. I just need the simulation, and not the text. Is it possible to do this?

Thanks in advance.

[dennisseda]

Hi,

I would like to embed the .jar file into my website as part of a quick reference guide. I just need the simulation, and not the text. Is it possible to do this?

Thanks in advance.

** sorry for the double post...

[Fu-Kwun Hwang]

Click embed button just below the applet will give you the following html code

Code:

<applet code='users.ntnu.fkh.browianmotion2type_pkg.browianmotion2typeApplet.class' archive='http://www.phy.ntnu.edu.tw/ntnujava/ejsuser/2/ejs_browianmotion2type.jar' name='browianmotion2type8403' id='browianmotion2type8403' width='540' height='595' mayscript=true>
<param name='draggable' value='true'>
</applet>

You can change the archive URL to URL at your web site if you upload the jar file to your server.

[diinxcom]

-*-
Just bookmark...
I will read it latter. Thanks

[CL-Devil]

Thank you very much.

[Fu-Kwun Hwang]

add t value bar

Embed a running copy of this simulation
<applet code='users.ntnu.fkh.browianmotion2_pkg.browianmotion2Applet.class' archive='http://www.phy.ntnu.edu.tw/ntnujava/ejsuser/2/ejs_browianmotion2.jar' name='browianmotion211363' id='browianmotion211363' width='742' height='822' mayscript=true><param name='draggable' value='true'></applet>
Embed a running copy link(show simulation in a popuped window)
<a href='http://www.phy.ntnu.edu.tw/ntnujava/msg.php?smfejs=11363' target='smfejs'>Run simulation</a>

Full screen applet or Problem viewing java?Add http://www.phy.ntnu.edu.tw/ to exception site list
Press the Alt key and the left mouse button to drag the applet off the browser and onto the desktop. This work is licensed under a Creative Commons Attribution 2.5 Taiwan License

• Please feel free to post your ideas about how to use the simulation for better teaching and learning.
• Post questions to be asked to help students to think, to explore.
• Upload worksheets as attached files to share with more users.

Let's work together. We can help more users understand physics conceptually and enjoy the fun of learning physics!