Radioactive nuclei decay law

[Fu-Kwun Hwang]

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Assume the number of radioactive nucleus is N(t) --- not yet decayed into daugheter product.
Each nucleus has the same probability p (p<1) decayed into daughter product.
It means that dN(t)/dt= -p*N(t) , where dN(t) is the number of nucleus decayed into daughter product at time t.
The solution is N(t)=N(0) e ^-pt, where N(0) is total number of nucleus at time t.

Each box represent a nucleus.
This applet let you set the probability for a nucleus to decay and watch how the number of decayed nuclei (color changed to RED)  increased with time t.

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[line17341]

[quote:a56ebe29b0="hwang"]This applet let you set the probability for a nuclei to decay and watch how the number of decayed nuclei change with time.[/quote:a56ebe29b0]

 Where can i keep something like that? :X

[Fu-Kwun Hwang]

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Get click the above "GET APPLET FILE" button (at the end of the first message)!


Here is another simulation I have created many years ago (not with EJS).
It shows a series of radioactive nuclei decay: different color represent different nucleus.
The radioactive nuclei will decay into daughter product, and the daughter nucleus will decay another nucleus.
The original nuclei are color code in BLACK.
It will decay into RED -> GREEN -> YELLOW -> BLUE (and become stable nuclei).

You can change decay time (unit: second) for each stage (from black -> red -> green -> yellow -> blue),
click start and watch how the number of different nuclei changed with time -- colored traces.

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[bunia]

    What means p?

[lookang]

p is Nuclear Decay Probability
http://hyperphysics.phy-astr.gsu.edu/hbase/nuclear/halfli2.html

i am trying to make n variable into a dynamically selectable slider.
but i can't seems to do it quickly.

my thoughts:
data is an array [n]*[n].
when n is changed in the slider, the data is not changed. why? what must be done to make an applet that allows of changes of number of atoms?

[lookang]

i am exploring remixing this applet into
http://66.7.205.91/~lookangc/index.php?topic=707.msg1442#msg1442

radioactive decay of parent isotope to daughter D to further daughter S.

u can download all 3 files n run the html to see my applet made in Netlogo 3.0.2.

thinking of using Ejs to improve the version

[lookang]

http://66.7.205.91/~lookangc/netlogo/Decay01.html
can
see ?
i wish to redo it in EJs, using your existing code here, is it ok?

[lookang]

hope to get some pointers how to get the EJs version "n" to be selectable by the slider, like mentioned in my early posts

Just figure out how to embed Netlogo applets

[Fu-Kwun Hwang]

I downloaded your attached xml files from previous message.
It seems that you want to be able to modify the nxn array from 40-400.
This will need a lot of memory when you have 400*400 cells.
I modified it and it can be chaged from 40-200.
1. You need to allocate the maximum number of cells needed.
2. The lattice GUI has been replaced with particleSet.

I did not understand why you want to modify range so I removed it.
Please check out the following modified version.

Embed a running copy of this simulation
<applet code='users.ntnu.fkh.decaychangeN_pkg.decaychangeNApplet.class' archive='http://www.phy.ntnu.edu.tw/ntnujava/ejsuser/2/ejs_decaychangeN.jar' name='decaychangeN4301' id='decaychangeN4301' width='724' height='507' 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=4301' target='smfejs'>Run simulation</a>

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• 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!

[lookang]

nice! thx for solving the n problem.

i will explore more when time permits.

That is what i need to figure out but couldnt!

1. You need to allocate the maximum number of cells needed.
2. The lattice GUI has been replaced with particleSet.

The range thing was my attempt by trial and error of how to control the size of the view, i was confused by n*n and range. Lucky u solved it so i can continue to learn by constructing a model with support from u. will seek guidance after finding out more whether can remix in my netlogo version.

Thanks a million boss!

[NagySandorIstvan]

Dear Prof. Hwang,
I have found a version of your simulation at http://www.phy.ntnu.edu.tw/oldjava/decay/decay.html
I am working on a web-based nuclear glossary for my students in Hungarian: http://www.chem.elte.hu/Sandor.Nagy/NewClearGlossy/index.html.
Is it possible to get the source code of that program?
The reason I am asking it, because the color scheme could be better. I think e.g. that a gray background would make the green text easier to read than the present background. I have also realized that the parameter "tau" is actually the half-life which should be denoted by T_1/2, or at least by T, because tau is used for denoting mean life in nuclear chemistry and physics.
Otherwise I like the applet very much. I am adding a supporting page to my glossary with an introductory page to your program. As soon as I upload it to the server, I will send you the link to it.
Best regards,
Sandor
PS: here is my home address if you want to react:
nasa@enternet.hu

[Fu-Kwun Hwang]

You can find the source code decay.java as attachement file of the third message.
Those labels can be modified as parameters for applet tag.

You need to modified the source code for the background color.

<applet width="600" height="340" codebase="/java/decay/" code="decay.class"><param value="reset" name="Reset" /><param value="start" name="Start" /><param value="time=" name="Time" /><param value="decay time tau1" /><param value="τ2" name="tau2" /><param value="τ3" name="tau3" /><param value="τ4" name="tau4" /></applet>

[NagySandorIstvan]

Dear Prof. Hwang,
Thank you for the instructions you gave me. Here is the link where you can find the Hungarian version of your great simulation:
http://www.chem.elte.hu/Sandor.Nagy/NewClearGlossy/Java/4StepSeries_Hwang/index.html
Attached please find the java with the new color scheme. I hope you will like it.
Very best regards,
Sandor

[diinxcom]

-*-
Content on this thread so help me. Thanks