Monday, September 30, 2013

curation circular motion

preparing for a meeting for curation of circular motion resources
thanks to kian wee for using my simulations!
http://www.compadre.org/osp/filingcabinet/bookmarks.cfm?FID=35638
Ejs Open Source Uniform Circular Motion Derivation of a = v^2/r
http://weelookang.blogspot.sg/2010/07/ejs-open-source-uniform-circular-motion.html
https://dl.dropbox.com/u/44365627/lookangEJSworkspace/export/ejs_users_sgeducation_lookang_circularmotionwee02.jar
author: fu-kwun hwang and lookang


To link to this folder, use:
http://www.compadre.org/OSP/filingcabinet/share.cfm?UID=12664&FID=35638

This link will only allow users logged into the comPADRE network access to your shared folders.

To allow public access to your public folders, provide this link:
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This link will allow users that have not logged into the Open Source Physics collection access to your shared folders. It may be useful if you wish to blog about your folder, or otherwise provide students, colleagues, or members of the general public direct access to your shared folders


Folder Folder Circular Motion
FolderCircular Motion  (14 resources)
Circular Motion
 
Ejs Open Source Uniform Circular Motion Derivation of a = v^2/rhttp://weelookang.blogspot.sg/2010/07/ejs-open-source-uniform-circular-motion.html
https://dl.dropbox.com/u/44365627/lookangEJSworkspace/export/ejs_users_sgeducation_lookang_circularmotionwee02.jar
author:  fu-kwun hwang and lookang
 
 
 
js Open Source Phase Difference Java Applet by lookang based on a original applet by Andrew Duffy http://www.compadre.org/osp/items/detail.cfm?ID=10014
http://weelookang.blogspot.sg/2012/07/ejs-open-source-phase-difference-java.html
https://dl.dropbox.com/u/44365627/lookangEJSworkspace/export/ejs_users_sgeducation_lookang_reference_circle_v2wee.jar
author: andrew duffy and lookang
 
Tracker Modeling in Uniform Circular Motion of Fan: Model is fr = -w*w*r where r0 = 0.358 m, ?0 = 124.3 deg, w0 = 236.0 deg/s
http://weelookang.blogspot.sg/2012/08/tracker-modeling-in-uniform-circular.html
https://dl.dropbox.com/u/44365627/TrackerDigitalLibrarySG/Tracker%20HCI%20JitNing%202012%20Sharing%20with%20Beginning%20Teachers/circularmotion%20fan/uniformcircularmotionfan.trz
author: lookang for model, jitning for video
 
http://weelookang.blogspot.com/2010/06/ejs-open-source-circular-motion-and.html
Ejs Open source Circular Motion and Centripetal Force java applet F = m*v^2/r
https://dl.dropbox.com/u/44365627/lookangEJSworkspace/export/ejs_users_sgeducation_lookang_CircularMotion_Circularmotion347.jar
author: fu-kwun hwang and lookang
 
Ejs Open Source Horizontal Circular Motion of Mass on a table java applet
http://weelookang.blogspot.sg/2010/07/ejs-open-source-horizontal-circular.html
https://dl.dropbox.com/u/44365627/lookangEJSworkspace/export/ejs_users_sgeducation_lookang_circular3dfr02.jar
author: fu-kwun hwang and lookang
 
 
 
picture of vertical circular motion by selecting g = 9.81 m/s^2
http://weelookang.blogspot.com/2010/07/ejs-open-source-vertical-circular.html
https://dl.dropbox.com/u/44365627/lookangEJSworkspace/export/ejs_users_sgeducation_lookang_circularvwee03.jar
author: fu-kwun hwang and lookang
 
 
Lec 5 | 8.01 Physics I: Classical Mechanics, Fall 1999
Circular Motion - Centrifuges Moving - Reference Frames - Perceived Gravity
View the complete course: http://ocw.mit.edu/8-01F99
Instructor: Prof. Walter Lewin

License: Creative Commons BY-NC-SA
More information at http://ocw.mit.edu/terms
More courses at http://ocw.mit.edu
 
Paul Hewitt demos centripital force by taking a bucket full of water and hurling it over his head and the class.
 

Friday, September 27, 2013

Basic Rocket JS Model

Basic Rocket JS Model re made into a JavaScript (JS) Model for running on most mobile device browser.
reference: http://www.compadre.org/osp/items/detail.cfm?ID=11294 by Larry Engelhardt

http://weelookang.blogspot.sg/2013/09/basic-rocket-js-model.html
Basic Rocket JS Model
author: Larry Engelhardt and lookang (this JS model)
online: https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejss_model_rockettemplatelookang04/rockettemplatelookang04_Simulation.html
offline: https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejss_model_rockettemplatelookang04.zip
source code:
https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejss_src_rockettemplatelookang04.zip




http://weelookang.blogspot.sg/2013/09/basic-rocket-js-model.html
Basic Rocket JS Model
author: Larry Engelhardt and lookang (this JS model)
online: https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejss_model_rockettemplatelookang/rockettemplatelookang_Simulation.html
offline: https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejss_model_rockettemplatelookang.zip
source code:
https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejss_src_rockettemplatelookang.zip


Rocket Launch - Project Template

This is an incomplete EJSS template for the "Modeling a Rocket Launch with Gravity and Air Resistance" project. Modify this template (source code here) to complete the project as described in the PDF document available at http://www.compadre.org/osp/items/detail.cfm?ID=11294.


completed by lookang for sharing with Hillgrove Secondary School
for the Broadening Learning horizons through flight and aerospace niche area.

changes made:

  1. re created (yes, you need to re-do this completely) the EJSS model referencing the original model by Larry Engelhardt
  2. blue sky is now a rectangle object instead of a image
  3. converted Events to Fixed relationship with minor tweaks to the codes
  4. released a version 04 because of a bug i cannot solved, by removing the additional close up panel and no polygons drawn now



Tuesday, September 24, 2013

Electric Potential Model by Wolfgang Christian

Electric Potential Model by Wolfgang Christian
reference: http://www.compadre.org/osp/items/detail.cfm?ID=11443



Electric Potential Model in 3D surface plot view superposed with the 2 charges system of Q2=-1 and Q1=+1
http://weelookang.blogspot.sg/2013/09/electric-potential-model-by-wolfgang.html
author: wolfgang christian and slightly edited by lookang (this version)
https://dl.dropboxusercontent.com/u/44365627/lookangEJSS/export/ejs_model_PointChargeElectricPotentialwee.jar
https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejs_model_PointChargeElectricPotentialwee.jar

Electric Potential Model in 3D surface plot (tilted) view superposed with the 2 charges system of Q2=-1 and Q1=+1
http://weelookang.blogspot.sg/2013/09/electric-potential-model-by-wolfgang.html
author: wolfgang christian and slightly edited by lookang (this version)
https://dl.dropboxusercontent.com/u/44365627/lookangEJSS/export/ejs_model_PointChargeElectricPotentialwee.jar
https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejs_model_PointChargeElectricPotentialwee.jar

Electric Potential Model in 3D surface plot view (vertically downwards like most 2D plots) superposed with the 2 charges system of Q2=-1 and Q1=+1
http://weelookang.blogspot.sg/2013/09/electric-potential-model-by-wolfgang.html
author: wolfgang christian and slightly edited by lookang (this version)
https://dl.dropboxusercontent.com/u/44365627/lookangEJSS/export/ejs_model_PointChargeElectricPotentialwee.jar
https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejs_model_PointChargeElectricPotentialwee.jar

Electric Potential Model with equipotential lines
http://weelookang.blogspot.sg/2013/09/electric-potential-model-by-wolfgang.html
author: wolfgang christian and slightly edited by lookang (this version)
https://dl.dropboxusercontent.com/u/44365627/lookangEJSS/export/ejs_model_PointChargeElectricPotentialwee.jar
https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejs_model_PointChargeElectricPotentialwee.jar

this is a legal remix version by lookang

changes made:

  1. added text array Q1, Q2, Q3 Q4 etc.
  2. added visualization colormode range from 0 to 9
  3. redesign the control panel to at the bottom
  4. table of the right
  5. made surface appear together with the charges for self manipulation to get 3D superposed view




text taken from http://www.compadre.org/osp/items/detail.cfm?ID=11443


Point Charge Electric Potential


The Point Charge Electric Potential model shows the electric potential produced by N point charges. Charges can be arranged in a ring, a line, or in parallel lines and the charge Q can alternate in sign. Custom configurations can be created by dragging particles or by entering xy and Q values into a data table. Blue (red) indicates a region of negative (positive) electric potential. The value of this potential V(x,y) is displayed in a text-box near the bottom of the view when the mouse is pressed.

Credits:

The Point Charge Electric Potential model was developed by Wolfgang Christian using the Easy Java Simulations (EJS) modeling tool version 4.3.4. You can examine and modify the model for this simulation if you have EJS installed by right-clicking within the program and selecting "Open Ejs Model" from the pop-up menu.

Information about EJS is available at: <http://www.um.es/fem/Ejs/> and in the OSP ComPADRE collection <http://www.compadre.org/OSP/>.

Monday, September 23, 2013

2D Charge Particles Model by Wolfgang Christian

this is a remixed of Point Charge Electric Field Demo Model written by Wolfgang Christian.

http://weelookang.blogspot.sg/2013/09/2d-charge-particles-model-by-wolfgang.html
2D Charge Particles Model by Wolfgang Christian
author: Wolfgang Christian and this version slightly edited by lookang
https://dl.dropboxusercontent.com/u/44365627/lookangEJSS/export/ejs_model_PointChargeElectricFieldDemowee01.jar
https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejs_model_PointChargeElectricFieldDemowee01.jar


changes made:
  1. redesign the panel for control to be bottom
  2. added more options to the menu for ease of use
  3. made the drawing of charges proportional to the charges
  4. made the collision detection to pause when the test charge is inside the charges
  5. added evolution page to reflect the physics of motion
  6. added test mass, m = 1 kg
  7. added trail to show path of test charge that can be drag away and it will start from vx=vy=0



text taken from http://www.opensourcephysics.org/items/detail.cfm?ID=10312

Point Charge Electric Field Demo


The Point Charge Electric Field Demo model shows the electric field with multiple point charge configurations and vector field visualizations. Users can select these configurations from a drop down menu or can create their own configurations.


The electric field is defined as the force per unit charge that would be experienced by a very small test charge at a given location. The Point Charge Electric Field Demo model shows an ideal test charge with an arrow that represents the field at the test location. The numerical field magnitude is shown in a text-box near the bottom of the view as the test charge is dragged.

Because the electric field changes dramatically in the vicinity of a charged particle, it is difficult to visualize its global properties using only a single test charge. A good way to visualize the field's geometric structure is to use a test-charge grid. Test charges are placed uniformly and the force per unit charge is shown at each test charge location. Users can select the number of locations and can use either arrow length or brightness (gray-scale) to show the field's magnitude a the grid point.

Teaching Objectives

Forces, Energy and Fields


Attractive and repulsive interactions at a distance (e.g., gravitational, magnetic, electrical and electromagnetic) can be described and explained using a field model.

Learning Goal

Students understand that the field model explains how objects exert attractive and repulsive forces on each other at a distance: their fields are the agents of the interaction.

Essential Knowledge

The field of a source (e.g., a particle with charge) depends only on the properties of the source and the position of an object relative to the source, not on any properties of objects placed in the field (e.g., a test charge). The field of an object is always there, even if the object is not interacting with anything else.

The strength of the electric field at a certain location is given by the electric force per unit of charge experienced by a test object placed at that location. If the electrical field at a certain position is known, then the electrical force exerted by the sources of that field on any object at that position can be calculated by multiplying the field strength (E) and the charge of the object.

Credits:

The Point Charge Electric Field Demo model was created by Wolfgang Christian using the Easy Java Simulations (EJS) modeling tool version 4.3.1. You can examine and modify the model for this simulation if you have EJS installed by right-clicking within the program and selecting "Open Ejs Model" from the pop-up menu.

Information about EJS is available at: <http://www.um.es/fem/Ejs/> and in the OSP ComPADRE collection <http://www.compadre.org/OSP/>.

Coulomb Force Model by Anne Cox

Coulomb Force Model by Anne Cox, Francisco Esquembre, Wolfgang Christian and now slightly edited by lookang.
taken from http://www.opensourcephysics.org/items/detail.cfm?ID=9683

Coulomb Force Model
http://weelookang.blogspot.sg/2013/09/coulomb-force-model-by-anne-cox.html
author: Anne Cox, Francisco Esquembre, Wolfgang Christian and lookang (this version)
https://dl.dropboxusercontent.com/u/44365627/lookangEJSS/export/ejs_model_CoulombForcewee01.jar
https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejs_model_CoulombForcewee01.jar


made some changes:
  1. redesign the control panel
  2. added finer control of position x and y 
  3. added Q slider that remembers the state of the charges


write-up taken from http://www.opensourcephysics.org/items/detail.cfm?ID=9683

Coulomb Force Model

The EJS Coulomb Force model shows the force vectors on charges. Users can change charge of an individual charge and add more charges (maximum: 10). Users can examine the model if Ejs is installed.
Exercises:
Run the simulation. Move the charges around and observe the force vectors (as well as the magnitude of the force). When the charges are the same size, are the forces equal and opposite? What about when the charges have different values (the physical size of a charge in the simulation changes with the charge value as a visual cue). The drop down menu allows you to select the charge (by color) that you want to change.
Add a third charge using the Add Charge button. With three charges, how can you arrange the charges so that the force on the red charge is zero? Sketch this configuration. If you change the charge of the red one, is the force still zero? Explain.
What is wrong with the following statement from a student? "When there are three charges (q=1 for all), the force on all three charges should be bigger than when there were only two charges (q=1 on each) because there is now a bigger total charge and the Coulomb force is proportional to charge."
Add a number of charges. Can you still set things up so that the force on the red charge is zero? Explain.

References:

Giancoli, Physics for Scientists and Engineers, 4th edition, Chapter 21 (2008).

Credits:

The Coulomb Force Model was created by Anne Cox, Wolfgang Christian,and Francisco Esquembre using the Easy Java Simulations (EJS) authoring and modeling tool. Exercises written by Anne J Cox.

You can examine and modify a compiled EJS model if you run the program by double clicking on the model's jar file. Right-click within the running program and select "Open EJS Model" from the pop-up menu to copy the model's XML description into EJS. You must, of course, have EJS installed on your computer.

Information about EJS is available at: <http://www.um.es/fem/Ejs/> and in the OSP ComPADRE collection <http://www.compadre.org/OSP/>.

Most Significant Stories by co-PI of Java Simulations for Teaching and Learning

thanks for your teacher-co-PI stories.!
u can read mine here
no names are mentioned but okay if accidentally appear right?
number of schools in Java Simulations for Teaching and Learning and the scaling up efforts

Teacher A: personal development

What was the nature of the change?

The most significant change I have seen through the Co-PI role so far has been the improved structure of teaching.

How was it before you have used Java Simulation?

Prior to the ETD project, generally the ICT ideas that were used in my lessons were commonplace. And so the learning of students did not take off well as expected. Inspired ICT ideas, though refreshing, are not integrated properly in the lessons resulting from the lack of pedagogical guidance and testing in a classroom environment before scaling up.

Instructional sequencing of lesson elements relating to ICT was also not looked into. For example, question about whether the EJS works meaningfully for flipped classroom or collaborative setting was not raised.

There were also a number of unnecessary concerns due to logistics constraint which hindered us from progressing more using EJS.

How did the Change come about? What happened?

I was invited to be Co-PI in 2012 in forming a working team comprised of experienced teachers from various Junior Colleges and few MOE staffs. I started to learn the fundamental reasons behind various uses of EJS and its accompanying pedagogies in knowledge deepening. My interpretation on Self Directed Learning (SDL) and Collaborative Learning (CoL) was also improved over time. I can vividly remember that one of the members, Kenneth, sought clarification from teachers on this interpretation and this has opened up opportunity for everyone to relearn.

The unnecessary concerns that hindered me to use EJS initially were dispelled from the fact that there is a great support from a MOE staff, Loo Kang who showed us the customized friendly EJS. He patiently guided us along with the revision of the applet for our school project.

We started to work on the Edulab project together. Every school representatives gave their contribution and exchanged resources for project scaling during our active school terms. As an activator, we went on to influence our teachers to implement those lesson packages in our school environment for every physics student cohort in a systematic way.

Frankly, I learnt a lot while managing the project for my school. This has truly developed me to be an individual who is sensitive and mature in implementing ICT based lessons.

Why is this change significant?

This change is significant because it offered me the flexibility to redesign my instructions and evaluate the effectiveness. For example, each school can choose to do qualitative or quantitative study for their project based on our need. The close-knitted network with teachers from other schools also provided good reference in case if I need pedagogical guidance or to draw research results.


Teacher B: 

What was the nature of the change?

The students were able to experience a new method of learning, apart from the conventional whiteboard teaching and teacher-led discussion. This new method of learning is deemed to be more interactive (student-student interaction, student-software interaction, as well as added some fun element to the lesson. Results show that lesson’s mastery objectives can be achieved using this alternative lesson plan and thus present another option for teachers to consider when designing their lessons.

Furthermore, at the learner’s end, the use of Java simulation helps students to visualize certain hard to-visualize Physics concepts. This proves to be more effective than textbook diagrams and can be a good alternative to physical classroom demonstrations. The java simulations also allow students to experiment with different data inputs and replay the simulation which is un-achievable in the physical demonstration set ups.

At the teachers’ end, some of the teachers become more receptive to alternative teaching approaches after the project. Even for the teachers who were not directly involved in our research project, the positive research data provided a strong reason for them to rethink about current and future teaching approaches.

How was it before you became a Co-PI of the project?

My school or at least my department uses videos and classroom demonstrations extensively to help students visualize Physics concepts. I believe as science teachers / scientists and engineers, physics teachers values greatly the understanding and visualization of concepts. Due to the long standing teaching practices that we had, even the students were largely convinced that this is the way to go for learning Physics. Certainly, the teachers were also aware of useful java applets available online, but it was usually meant for teacher led discussion. We did not consider letting the students experiment with the java simulation and discussing in groups. Not to mention, the teachers did not thought that they can modify the java simulations according to their own professional needs.



Impact of NRF2011-EDU001-EL001: Java Simulation Design for Teaching and Learning

Teacher C:

What was the nature of the change?

The change I observed was the students’ ability to better appreciate the physical system that would not have been easy for the students. The java simulation on Superposition brings across the meaning of superposition well and the various representations allow the students to think more deeply into the concepts.

The teacher also has a better understanding of the meaning of design inquiry worksheet. It provides the teacher with a platform to learn and experiment the worksheets that they created for the students. This serves to develop in the teachers new skills and appreciation of the worksheet’s design.

How was it before you have used Java Simulation?

Prior to the project, the teacher could only rely on the ripple tank experiment, the use of transparency and videos to illustrate the concepts. The students were unable to manipulate the variables and they could probably see the effect of the resultant pattern if they are sharp. Use of two waves on transparency has its limitation too as it was not easy to print the wave-front correctly.

How did the Change come about? What happened?

Java simulation has been available for some time but the ability to make changes to the parameters and design of the interface are something that added value to the java simulation. Loo Kang has been exploring changing the interface and adding value to the various simulations for quite some time and his ability to work with the schools on changes needed help a lot. Teachers could now seek his help to make changes and this has changed and improved the original version of the simulation. The added feature in the simulation allows the students to better appreciate the concept in superposition.


Why is this change significant?

The change is significant in that it provides the teacher another platform to introduce this conceptually difficult topic of superposition. The multiple representations available in the java simulation provide an enriched perspective of how this topic could be understood. As the java simulation is easily available over the internet, it allows students to exercise more self-directed learning as they could explore the various parameters on their own.


Teacher D:

What was the nature of the change?

Improved student understanding of abstract and difficult physics concepts and increased motivation to use multimedia teaching tools among teachers

How was it before you became a Co-PI of the project?

Traditionally there are some physics topics which are more difficult to comprehend than others. An example of such topics is Gravitation. Many students are not able to visualize the gravitation effect between huge masses, like planets and satellites, and there are very little, if no, meaningful experiments that can be carried out in a school science lab to investigate gravitational laws. Hence teachers usually rely on qualitative description and pictures or videos to illustrate the concepts. However these methods are mostly passive and many students find it difficult to comprehend the unfamiliar concepts correctly without interactive engagement.

How did the Change come about? What happened?

In our search for better teaching methods to support students’ learning, Mr Wee Loo Kang, ETD officer, introduced us to four of his newly designed Easy-Java-Simulation (EJS) that allow users to manipulate variables and observe the invisible effects through simulations. One of the EJS even allows students to visualize planetary motions in 3 dimensions. The graphic is of high quality and the manipulation is not too difficult. The four EJS were used to support lectures and infused strategically either in the existing tutorial questions or designed as an inquiry worksheet, to enhance students’ understanding. These EJS also served as platforms for students’ self-directed learning and collaborative learning.

Why is this change significant?

Based on perceptive survey and small group interviews, most students enjoyed the learning process and claimed that they have gained deep understanding of the concepts. Teachers have also commented that there were improved learning attitude among their students with the introduction of the EJS.

why schools should adopt adapt these gravity computer models

why schools should adopt adapt these gravity computer models?




Reasons for considering using these simulations include:

  1. Developed with YJC, IJC, RVHS, AJC, SRJC, SAJC, NJC in level wide implementations or class level. 
  2. Innergy MOEHQ GOLD award 2012 winner
  3. Shared at 5th IPSG, 5th redesign pedagogy conference 2013 and multimedia in physics teaching and learning (MPTL18) conference 2013
  4. Published in physics education journal
  5. Free for anyone to use, remix and redistribute, licensed creative commons attribution.


And yes, I personally teach field vectors in place of field lines because field vectors (what you get with many equal distance compasses in an area ) is easier to produce in computers models and students can use this concept in daily lives better than field lines (I doubt anyone can compute field lines in their minds accurately).

Gravitational Field
How to measure radius of Earth by Eratosthenes  
Ejs Open Source Eratosthenes Measures Earth Java Applet by Todd Timberlake, remixed by lookang, version public domain earth from Tom Patterson, www.shadedrelief.com. Thanks Todd and Tom!
http://weelookang.blogspot.sg/2012/06/ejs-open-source-eratosthenes-measures.html
https://dl.dropbox.com/u/44365627/lookangEJSworkspace/export/ejs_Eratostheneswee.jar
author: timberlake and lookang

Gravitational field Kepler's 3rd Law T^2/r^3=constant
Gravitational field Kepler's 3rd Law T^2/r^3=constant @YJC 

version 20August 2013. http://weelookang.blogspot.com/2010/06/ejs-open-source-kepler-system-model-by.html
prototype: https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejs_KeplerSystem3rdLaw09.jar
older version:https://dl.dropbox.com/u/44365627/lookangEJSworkspace/export/ejs_KeplerSystem3rdLaw03.jar
author: timberlake and lookang
worksheets by (lead) YJC: same link of four simulations https://www.dropbox.com/s/53vztw6meupn4r5/GravitationYJC.zip





• Force between point masses
• Field of a point mass
Field near to the surface of the Earth
http://weelookang.blogspot.sg/2010/10/ejs-open-source-gravity-field-model.html
Ejs Open Source Gravity Field Model Near Earth Java Applet
https://dl.dropbox.com/u/44365627/lookangEJSworkspace/exportarchived/ejs_users_sgeducation_lookang_gravityfield1.jar
author: lookang based on the works of fu-kwun hwang
Gravitational potential 1 Dimension



added g proportional to r inside sphere of constant density as suggested by tatleong. re-implemented dotted lines of g1 g2 and phi1 and phi2 with no lag after using the group to contain them.
https://dl.dropbox.com/u/44365627/lookangEJSworkspace/export/ejs_GField_and_Potential_1D_v7wee.jar
for RVHS computers https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejs_EarthAndSatelite4.3.6.jar
author: lookang and andrew based on andrew duffy early model
worksheets by (lead) YJC: same link of four simulations https://www.dropbox.com/s/53vztw6meupn4r5/GravitationYJC.zip
Gravitational potential 1 Dimension Earth & Moon Real Data 
version April 30 2013 http://weelookang.blogspot.sg/2010/08/ejs-open-source-gravitational-field_10.html 
picture of computer model of Earth and Moon gravity system,
added white background option for printing on lecture notes, fixed bug of g2 showing, latex for g and phi,menu for Earth Moon configuration instead of just Moon Earth previously
https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejs_GFieldandPotential1Dv7EarthMoon.jar
author: lookang and andrew based on andrew duffy early model
worksheets by (lead) YJC: same link of four simulations https://www.dropbox.com/s/53vztw6meupn4r5/GravitationYJC.zip


Gravitational Field Vector, Field Lines, Potential in 2 Dimensions
Ejs Open Source 2 Mass Model with Gravity Field Vector, Field Lines, Potential updated 06 sept 2011 with potential and field strength values
http://weelookang.blogspot.sg/2011/09/ejs-open-source-2-mass-model-with.html
https://dl.dropbox.com/u/44365627/lookangEJSworkspace/export/ejs_users_sgeducation_lookang_twopointmass06.jar
author: fu-kwun hwang and lookang
Gravitational Earth Projectile Orbit Newton's Mountain 





http://weelookang.blogspot.sg/2013/06/newtons-mountain-simulation-enhanced.html
http://weelookang.blogspot.sg/2011/05/ejs-open-source-newtons-mountain.html
added ability to fire to add velocity to a achieve eclipse orbit and select circular to achieve circular orbit by applying impulse in directions to get velocity at the correct speed and direction, perpendicular to radius. this feature helps in the learning of energies change as satellite move from one circular orbit to another circular as requested by soo kok.
https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejs_NewtonsMountainwee06.jar
author: timberlake, lookang and fu-kwun hwang 




http://weelookang.blogspot.sg/2011/05/ejs-open-source-newtons-mountain.html
white out background for inserting  pictures into tutorials with y = 4.23E07 m and vi = 3070.98 m/s
https://dl.dropbox.com/u/44365627/lookangEJSworkspace/export/ejs_NewtonsMountainwee.jar

author: timberlake and lookang


Geostationary Orbits of Satellite & Earth
version 18 April 2013 with added input zoom field and keyboard shift+mouse to zoom works again
http://weelookang.blogspot.sg/2010/07/ejs-open-source-geostationary-satellite.html
author: lookang based on the works of paco
https://dl.dropbox.com/u/44365627/lookangEJSworkspace/export/ejs_EarthAndSatelite.jar
worksheets by (lead) YJC: same link of four simulations https://www.dropbox.com/s/53vztw6meupn4r5/GravitationYJC.zip

Sunday, September 22, 2013

how to create JavaScript EJS models

how to create JavaScript EJS models?

Assuming you already know a bit about EJS 4.3.7 this tutorial aims to introduce some of the key features as unveil during MPTL18 by Professor Paco, creator of Easy Java Simulation, an authoring tool-kit for physics models.



  1. after launching EJS console.jar, select Programming language to Javascript instead of Java
    Javascript
  2. a new authoring environment will be launched that looks pretty much similar except with the obvious difference of the HtmlView 
    EJS5.0 Beta with Javascript authoring environment 
  3. since this is a beta, but it is pretty compete with the usual radio buttons like Description, Model and HtmlView. Users of EJS 4.3.7 used to Java will have to reprogram the codes into their new Javascript model. ( Yes, there is currently no automatic cross conversion of sort, authors need to recreate their new models in the new environment ( copy and paste only works between Javascript models, and not between Java and Javascripts models)
  4. There are some useful examples already available in the comPadre Library, to get to the library click on the "Read from an EJS library icon" just below the save, save as and search icon.
    Read from an EJS library icon
  5. Click on the Get Catalog and search for "ejss" as a search keyword and all the EJSS models will be available for download and you can copy and paste some of the elements and codes ( with modification ) into your own fresh model that you want to recreate.
    search for "ejss" 
  6. click on any of the models that you wish to examine to learn how to program, click on the download
    comPadre digital EJSS models listed
  7. EJSS will prompt you to save the model, i recommend saving it into a new folder "EJSS" where i choose to keep all EJSS models, fundamentally they are different and currently do not require saving into the users/sgeducation/lookang folder.
    save into your source folder
  8. click on the compile or run model button 
    ferrisWheelJS model by professor mario

  9. and EJSS will take care of the rest and run in a emulator
    EJSS emulator view
  10. i manage to create a simpler model that EJSS currently seems to be able to generate here http://weelookang.blogspot.sg/2013/09/one-dimension-collision-js-model.html


    One Dimension Collision JS Model
    author: lookang
    Online: https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejss_model_Momentum1D01/Momentum1D01_Simulation.html
    Download: https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejss_model_Momentum1D01.zip


  11. click on the dropbox link and enjoy!
  12. there is a lot to play with and great potential to introduce students to make physics models :)