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Easy Java Simulations (2001- ) => Collaborative Community of EJS => Topic started by: lookang on January 06, 2011, 11:12:42 pm

Title: Ejs Open Source Magnet Falling Through Ring Model Java Applet
Post by: lookang on January 06, 2011, 11:12:42 pm
Ejs Open Source Magnet Falling Through Ring Model Java Applet remix by lookang

this is a remixed of the original model http://www.compadre.org/osp/items/detail.cfm?ID=10327
by  Francisco Esquembre

The Magnet Falling Through Ring model shows the dynamics and the induced current (voltage) when a magnet falls through a conducting ring.

The current in the ring is computed by electromagnetic induction using to Faraday's law and the induced emf is proportional to the negative of the rate of change of magnetic flux. The direction of the induced current is determined by Lenz's law, the induced current produces magnetic field which tends to oppose the change in magnetic flux that induces such currents.

Title: Re: Ejs Open Source Magnet Falling Through Ring Model Java Applet
Post by: lookang on January 06, 2011, 11:18:18 pm

1 redesign the layout to fit my usual format
2 added text on green electrons for eye-balling purposes
3 set initial r = 0.1 instead of the usual 0.03, the electrons are moving too fast for r=0.03
4 add magnetZs as slider for the initial magnetZ, modified the codes slightly magnetZ = freeFallZ = magnetZs/4 ; // insead of the older code = maximum/4
5 bug the text didn't compile in Java3D so i did it on simple3D

to do list
to add the model for a cylinder ?, currently it is only for a ring of very small Z thickness

Title: Re: Ejs Open Source Magnet Falling Through Ring Model Java Applet
Post by: lookang on February 03, 2012, 09:06:43 pm
Update of Action Research by teacher
Extending from the last meeting on 27 Feb January. I indicated my action research will be based on EMI. This morning I just have a level meeting and we have decided to implement the EJS before EMI lecture instead of tutorial week. This means that my turn around time for this project has shortened. Naturally, EJS could be implemented just before lecture as home task to increase learning gain from lecture. So, my team has agreed to test out the EJS according to the following general plan.

the research study has a flaw timing of inquiry through computer model then lecture, how can unguided self directed inquiry be considered as learning? some human support is needed for learning to occur besides the worksheet. just my sense now. :)

EP: Initially, we have considered to have it as tutorial style but since we wanted to know if students could learn better just before the lecture rather than after. According to Mr Sng, there was a paper written on effectiveness of lecture. It mentioned that "higher learning gain if students undergo some form of problem first follow by lecture. So we are thinking letting students struggle on their own first using the EJS pkg, follow by the lecture so called "human support". Moreover, if this is really effective, we shall have implemented this as elearning within SOW so it will not disrupt much any of the normal conventional running of tutorial.

Experimental Grp: 8 Classes of about 25 students (each from one teacher)
Control Grp: remaining classes
Treatment: Use of self-directed learning using EJS and instructional home-worksheet before the actual lecture exposure

i worry instructional home-worksheet is not enough.
perhaps a YouTube that also shows the procedural steps and thinking questions?
a discussion forum NTNU? http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=2066.msg8963#msg8963 or AJC one? for collaborative sense making?
perhaps a YouTube that also shows the procedural steps and thinking questions??

EP: I will feedback to my team about the You Tube procedural steps and thinking qns. Good advise.

Measurement: Post treatment 2 Tier MCQ (15 qns) *Open ended qns for 2nd Tier (right after lecture)

i am curious 15 questions and Short structure question SSQ all on magnet falling then it is valid.
EP: Sorry, I did not mentioned to you, Yes all will be related to falling magnet.

As EMI lecture is closing in in 3 weeks time, I would like to give you a headup.
EJS applet Customisation
In view of the learning need, I like to give our input to EJS applet on EMI (Falling Magnet on the ring). Appreciate you could customise the applet accordingly.
We need the applet
1. to simulate two lengthwise-jointed magnets falling into the coil. Common misconception: emf value peak will double.

i see, double length, same emf peak further apart
the model cannot be done yet refer to http://www.opensourcephysics.org/bulletinboard/TDetails.cfm?TID=2180 for discussion with paco

EP: Yes, same emf peak.

picture from teacher
2. to simulate magnet falling through another solenoid of length longer than that of magnet. A graph to show zero emf value for magnet fall within the solenoid.

picture please (world view and graph)
cannot be done yet, need paco to help, currently it is valid for a ring

3. to simulate two adjacently stickon magnets (unlike pole) falling into the coil. No induced emf will be produced.

picture please (world view and graph)
i can do this

from teacher
4. to simulate two adjacently tied magnets (like poles)  falling into the coil. Induced emf will be produced.  

picture please (world view and graph)
i can do this


5. to integrate area under half
refer to  of the emf graph. Presently, it can only show full area under entire graph. Good if student can realise that two section of areas are equal.
picture please (world view and graph) actually the |area| is larger as the magnet exit :) my mistake, |peak| is greater but area is the same

EP: See attachment. O yes, larger as magnet exit. I was thinking about magnet falling under terminal velocity. Does the applet about to simulate falling magnet under terminal spd? Just asking.

As there will be a review on this project next wed, please let me know if I could the updated my team on the applet with new changes mentioned.
EP: Really very sorry to trouble you. As for the worksheet, post test MCQs, I will be able to pass you after my internal meeting by wed.

If you have any reservation on the above, please let me know. I will glad to provide more information to you. Thanks in advance!! =)  

Title: Re: Ejs Open Source Magnet Falling Through Ring Model Java Applet
Post by: lookang on February 04, 2012, 10:00:59 am
good advice from research scientist

Thank you very much for kindly sharing this with me and involving me in the conversation – I do appreciate it.

Ee-peow, if you and your colleagues feel most comfortable with the methodology you have chosen, go ahead, because it is your research and you must own it :-)

What is critical for you to ask yourselves is:

How you might go about unpacking the learning process that the students go through as they use the Applet.

That is, which particular affordances of the Applet are being leveraged as the students learn the concept.

In other words, it is not so much important to demonstrate that the Applet works (which it will), but how and why it works.

This sort of thing is not easily done through Control / Experimental Design, but these questions are (from a wider institutional point-of-view) more important than simply knowing that the intervention is effective.

For it is only when we know how something works, that we are then able to think about how to diffuse and generalize the principles (but you know that already :-) )

So, do not just satisfy yourself with proving a Delta, for a Delta there will be.

Instead, go about seeking to understand why there is a Delta, and when you do so, you will understand how the project affords Assessment for Learning.

(I would like to take the opportunity to remind Lookang that it is the considered opinion (from previous meetings) that the project is best positioned as AfL; Lookang, you need to stop obsessing about how / whether the intervention is SDL/COL – those are red herrings which you keep being distracted by)

i was not me9(lookang), humping on SDL by the way.