## Wednesday, September 22, 2010

### Ejs Open Source Rolling Solid & Hollow Sphere with Slipping java applet

Ejs Open Source Rolling Solid & Hollow Sphere with Slipping java applet
« on: Today at 07:44:24 PM »
 http://weelookang.blogspot.sg/2010/09/ejs-open-source-rolling-solid-hollow.html Ejs Open Source Rolling Solid & Hollow Sphere with Slipping java applethttps://dl.dropboxusercontent.com/u/44365627/lookangEJSS/export/ejs_model_rotateDiskwee.jar https://dl.dropbox.com/u/44365627/lookangEJSworkspace/export/ejs_users_sgeducation_lookang_rotateDiskwee.jar author: Hwang Fu Kwun and lookang

Ejs Open Source Rolling Solid & Hollow Sphere with Slipping java applet
reference:
http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=150.msg6487#msg6487 by Hwang Fu Kwun original
http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=1801.0 by Hwang Fu Kwun original layout by Ahmed.

Java Applet below

Description:
Slipping and Rolling Sphere
The EJS Slipping and Rolling Sphere Model shows the motion of sphere rolling on a floor subject to a frictional force as determined by the coefficient of friction μk. The simulation allows the user to change the initial translational and rotational velocities of the wheel, v_i and ω_i, and the radius, mass and mass distribution momentum of inertia cofficeient, R, m, and C of the wheel. By controlling these variables, the dynamics of the wheel can be changed to show the slipping, then rolling without slipping, of the wheel.

Slipping and Rolling Object (Sphere or Cylindrical) Theory
The theory behind the simulation of the rolling and slipping sphere is relatively straightforward, but substantially differs from its simpler cousin: the rolling without slipping sphere. When a sphere rolls without slipping, v = ωR, where v is the linear or translational velocity of the wheel, ω is the angular or rotational velocity of the wheel, and R is the wheel’s radius. When this condition is maintained, the relative velocity between the bottom of the wheel and the ground is zero. This condition, therefore, also means that the frictional force that acts must be static friction which cannot do any work on the wheel, and energy methods can be used to analyze the motion.
For rolling with slipping, the force acting on the wheel is kinetic friction which must be treated both as a force, F, acting on the center of mass of the wheel and as a torque, τ, acting at the point of contact between the wheel and the ground. During this motion, both the force and the torque are constant and therefore the velocity and the angular velocity can be determined with the constant acceleration kinematics equations: v = v0 +(F/m)t and ω = ω0 +(τ/I)t, respectively The rotational and translational motions are then independent until v = ωR when the wheel begins to roll without slipping. The time when this occurs can be found with these kinematics equations solving for when v = ωR.
The simulation has these theoretical details explicitly encoded in it. Specifically:
The translation and rotational motions each have their own differential equation (ODE) describing the motion (dx/dt = v, dv/dt = F/m, dθ/dt = ω, and dω/dt = τ/I).
These two motions can be coupled in the same way that two-dimensional motion in x and y can be coupled, but the dynamics can be understood separately.
EJS makes it easy to model the coupled problem without messy mathematical manipulations with a lot of trigonometric functions. The Evolution page in EJS allows one to easily transform from the space to the body frame by changing the transform vectors. See the Evolution workpanel in EJS for details.
EJS differential equation solver (ODE) events allow us to determine precisely when slipping stops, v = ωR, and to switch the equations of motion from rolling with slipping (constant acceleration and constant angular acceleration) to rolling without slipping (constant velocity and constant angular velocity). See the ODE events page in EJS for details.

Exercises:
Questions
1. For an initially translating, but not rotating, wheel, draw a free-body diagram and determine the acceleration and the angular acceleration of the wheel for the time it is translating and slipping. Your answers should be written in terms of μk, v_i, C kw, m, and R.
2. For the scenario in (1), (a) determine the time the wheel is slipping, (b) determine the distance the wheel travels while slipping, (c) determine the final translational and rotational velocities when the slipping stops. Check your answer against the simulation.
3. Redo questions (1) and (2) for an initially rotating (with backspin), but not translating, wheel. Check your answer against the simulation.
4. Redo questions (1) and (2) for an initially rotating (with backspin), and initially translating, wheel. Check your answer against the simulation. Show that the condition for the wheel to end up stationary is that v_i = -v*ω_i*R*kw.

## Wednesday, September 15, 2010

### Using a Visualization-Based Interactive Instruction to Remediate Students’ Conceptual Difficulties in Electromagnetic Induction

Google Useful source of search key

Using a Visualization-Based Interactive Instruction to Remediate Students’ Conceptual Difficulties in Electromagnetic Induction

1. ### CHIA Teck Chee - NSSE Faculty

Using a visualization-based interactive instruction to remediate students' conceptual difficulties in electromagnetic induction (2008). MSc Theses ...
www.nsse.nie.edu.sg/faculty/tcchia.htm - Cached

2. ### NIE Digital Repository: Using a visualization-based interactive ...

Title: Using a visualization-based interactive instruction to remediate students' conceptual difficulties in electromagnetic induction. Authors: Lyna ...
repository.nie.edu.sg/jspui/handle/10497/2620 - Cached
3. [PDF]

### LEARNING ELECTROMAGNETISM WITH VISUALIZATIONS AND ACTIVE LEARNING

File Format: PDF/Adobe Acrobat - Quick View
by YJ DORI - Cited by 5 - Related articles
and visualization can potentially alleviate difficulties in students' understanding .... project was assessed using conceptual tests and a perception questionnaire. ..... Influence of interactive videodisc instruction using simultaneous-time .... Investigating electromagnetic induction through a microcomputer based ...
web.mit.edu/jbelcher/.../Chapter8_Dori_Belcher_FINAL_8_12_2004.pdf

## Tuesday, September 14, 2010

### Ejs Open Source AC power and current waveform java applet « on: Today at 07:31:34 PM »

Ejs Open Source AC power and current waveform java applet
« on: Today at 07:31:34 PM »

 http://weelookang.blogspot.sg/2010/09/ejs-open-source-ac-power-and-current.html Ejs Open Source AC power and current waveform java applet author: fu-kwun hwang and lookang https://dl.dropboxusercontent.com/u/44365627/lookangEJSS/export/ejs_model_sin2.jar https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejs_users_sgeducation_lookang_sin2.jar
Picture

Applet here

mirrored from
http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=1943.msg7126;topicseen#msg7126
this applet is made by Professor Fu-Kwun Hwang, remixed by lookang

## Saturday, September 11, 2010

### Ejs Open Source Bouncing Ball with Drag Java Applet « on: September 09, 2010, posted from:Singapore,,Singapore

Ejs Open Source Bouncing Ball with Drag Java Applet
« on: September 09, 2010, 05:54:04 PM » posted from:Singapore,,Singapore
 http://weelookang.blogspot.sg/2010/09/ejs-open-source-bouncing-ball-with-drag.html https://dl.dropboxusercontent.com/u/44365627/lookangEJSS/export/ejs_model_UpandDownBouncingBall.jar https://dl.dropbox.com/u/44365627/lookangEJSworkspace/export/ejs_users_sgeducation_lookang_UpandDownBouncingBall.jar author: lookang

kindly hosted by NTNUJAVA Virtual Physics Laboratory by Professor Fu-Kwun Hwang
http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=1940.0
alternatively, go direct to http://www.phy.ntnu.edu.tw/ntnujava/index.php?board=28.0
Author: lookang
http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=1940msg7108;topicseen#msg7108

this Model is made using the 4 equations
dx/dt = vx
dy/dt = vy
dvx/dt = ax
dvy/dt = ay
the event handler is zero crossing
if (vy<0) return yground-(y); // bounced at x=xmax
// else if(v<0)return xbumpertop-(x-carSize/2); // bounced at x=xmin or x+carSize/2
//return 1.0; // time will stop if use return 1.0
return 0; // time continues
Action is
vy=-e*vy;

Version 1: How to extend learning using Ejs simulation?

There are free for educational use technology tools that can be used to advance active learning with multiple representations as discussed eariler. The tracker (Brown, 2010) and simulations made using Easy Java Simulations (F. Esquembre, 2004; Francisco Esquembre, 2010) ) that can be used to support the existing learning strategy on the physics of a bouncing ball. For the purpose of illustration and possible future investigation, one such simulation is made using Ejs called the Ejs Open Source Bouncing Ball with Drag Java Applet (Wee, 2010) hosted in the NTNU Virtual Physics Laboratory Discussion Forum (Hwang, 2010).

Existing sample student pen and paper work can be illustrated through multi representations in the Ejs simulation.

Figure 1: Screen shot of a ball throw up and its motion

Notice the pen and paper work by student is represented through a simulation that evolves with time, with the similar representation of the displacement sy, velocity vy and acceleration ay. The equal time interval ball trail can be visualized from the world view representation

Figure 2: Screen shot of scientific graphical representation of a ball throw up and its motion after bouncing on the floor

Scientific graphical representation of the displacement sy, velocity vy and acceleration ay versus time t or displacement sy can be visualized even after bouncing off the floor, which can be difficult to rationalized in traditional pen and paper, it is possible to use simulations to allow students to socially construct meaning of the bouncing ball.

Figure 3: Screen shot of scientific graphical representation of a ball throw up and its motion after (elastic coefficient of restitution = 0.6) inelastic collision with the floor.

The simulation can easily be added with the scientific graphical representation of PE = m*(-ay)*sy, KE = 0.5*m*vy^2 and TE = PE+KE.

Figure 4: Screen shot of world view and scientific graphical representation of a ball throw up and under the influence of air resistance model Fd= k*vy its motion after (elastic coefficient of restitution = 0.6) inelastic collision with the floor

The benefits of a model model with scientific visualization allowed teachers to facilitate student learning and students can test out what if scenario safely, anytime, anywhere with suitable representations of physics quantities. This lesson example with the learning strategy is align with Singapore ICT Masterplan 3 in education (MOE, 2009) call for designing learning environments to support the development of self directness and collaborative skills in Singapore students. As teacher-researchers, we will draw on the our collective knowledge together with insights from Open Source Physics (Christian, 2010) community and PhET research simulations, to design simulation, develop and test out the process of learning (Wieman, Perkins, & Adams, 2008), to continually refined the simulation learning cycle.

Reference:

Brown, D. (2010). Tracker Free Video Analysis and Modeling Tool for Physics Education Retrieved 20 October, 2010, from http://www.cabrillo.edu/~dbrown/tracker/
Esquembre, F. (2004). Easy Java Simulations: A software tool to create scientific simulations in Java. Computer Physics Communications, 156(2), 199-204.
Esquembre, F. (2007). Easy Java Simulations Retrieved 13/03/2007, 2007, from http://www.um.es/fem/Ejs/Ejs_en/index.html

Version 2: How to extend learning using Ejs simulation?

There are free for educational use technology tools that can be used to advance active learning with multiple representations as discussed earlier. The tracker 1 and simulations made using Easy Java Simulations (hence fore Ejs) 2,3 that can be used to support the existing learning strategy on the physics of a bouncing ball. For the purpose of illustration and possible future investigation, one such simulation is made using Ejs called the Ejs Open Source Bouncing Ball with Drag Java Applet 4 hosted in the NTNU Virtual Physics Laboratory 5 Discussion Forum.
Existing sample student pen and paper work can be illustrated through multi representations in the Ejs simulation.
Figure 1: Pen Paper representation & Ejs simulation representation of a ball thrown up

Notice the pen and paper work by student is represented through a simulation that evolves with time, with the similar representation of the displacement sy, velocity vy and acceleration ay. The equal time interval ball trail can be visualized from the world view representation.

Figure 2: Pen Paper representation & Ejs simulation scientific graphical representation of a ball throw up and its motion after bouncing on the floor.

Scientific graphical representation of the displacement sy, velocity vy and acceleration ay versus time t or displacement sy can be visualized even after bouncing off the floor, which can be difficult to rationalized in traditional pen and paper, it is possible to use simulations to allow students to explore for many more bounces and socially construct meaning of the bouncing ball.

Figure 3: Pen Paper representation & Ejs simulation of scientific graphical representation of the energies of a ball throw up and its motion after bouncing with the floor.

The simulation can easily be added with the scientific graphical representation of PE = mass*g*y*(-1); KE =0.5*mass*(vx*vx+vy*vy); QE = -KE - PE + TEs; // a reverse way to calculate QE; and TEs = PE+KE when t = 0s;
The simulation allows for ease of visualization of time greater than one bounce.

Figure 4: Pen Paper representation & Ejs simulation of data analysis tool to derive the equation of best fit line of the form: y = a*t^2 +b*t +c where a = -4.905, b = 30, and c = 0 where the equation is s = y*t +0.5*a*t^2 is verified.

As for the symbolic representation, it is a pedagogical choice as well as a simulation design consideration. The teachers feel that learning can be meaningful if the students had to think about what they are analyzing. Thus Data Analysis tool in Ejs allows students to select points of the graphs to decide methods to a best fit line choice whether straight line, quadratic etc, rather than showing it on the Ejs view. The design consideration is there are already many variables shown in the applet, it might be visually overloading and lack of space to show the equations of motion shown as well.

Figure 5: Ejs simulation of world view and scientific graphical representation of a ball throw up and under the influence of air resistance model Fd= k*vy where k = 0.3 its motion after perfectly elastic collision with the floor.

The benefits of a model with scientific visualization allowed teachers to facilitate student learning and students can test out what if scenario safely, anytime, anywhere with suitable representations of physics quantities. This lesson example with the learning strategy is align with Singapore ICT Masterplan 3 in education 6 call for designing learning environments to support the development of self directness and collaborative skills in Singapore students. As teacher-researchers, we will draw on the our collective knowledge together with insights from Open Source Physics 3,7 community and PhET research 8 simulations, to design simulation, develop and test out the process of learning to continually refined the simulation design and learning cycle.

Reference:
1 Douglas Brown, "Tracker Free Video Analysis and Modeling Tool for Physics Education", (Open Source Physics comPADRE, USA, 2010), Vol. 2010.
2 F. Esquembre, "Easy Java Simulations", (2010), Vol. 2010.
3 F. Esquembre, "Easy Java Simulations: A software tool to create scientific simulations in Java," Computer Physics Communications 156 (2), 199-204 (2004).
4 Loo Kang Wee, Ejs Open Source Bouncing Ball with Drag Java Applet (2010).
5 F. K. Hwang, "NTNU Virtual Physics Laboratory", (2010), Vol. 2010.
6 MOE, "Third Masterplan for ICT in Education", (Ministry of Education Singapore, 2009), Vol. 2010.
7 F. K. Hwang and F. Esquembre, "Easy java simulations: An interactive science learning tool," Interactive Multimedia Electronic Journal of Computer - Enhanced Learning 5 (2003); Wolfgang Christian, "Open Source Physics (OSP)", (2010), Vol. 2010.
8 W. Adams, S. Reid, R. LeMaster, S. McKagan, K. Perkins, M. Dubson, and C. Wieman, "A Study of Educational Simulations Part II--Interface Design," Journal of Interactive Learning Research 19 (4), 551-577 (2008); Wendy K. Adams, Archie Paulson, and Carl E. Wieman, "What Levels of Guidance Promote Engaged Exploration with Interactive Simulations?," AIP Conference Proceedings 1064 (1), 59-62 (2008); Wendy K. Adams, Sam Reid, Ron Lemaster, Sarah B. McKagan, Katherine K. Perkins, Michael Dubson, and Carl E. Wieman, "A Study of Educational Simulations Part 1 -- Engagement and Learning," Journal of Interactive Learning Research 19 (3), 397-419 (2008); C. E. Wieman, W. K. Adams, P. Loeblein, and K. K. Perkins, "Teaching Physics Using PhET Simulations," Physics Teacher 48 (4), 225-227 (2010); Carl E. Wieman, Wendy K. Adams, and Katherine K. Perkins, "PhET: Simulations That Enhance Learning," Science 322 (5902), 682-683 (2008); Carl E. Wieman, Katherine K. Perkins, and Wendy K. Adams, "Oersted Medal Lecture 2007: Interactive simulations for teaching physics: What works, what doesn't, and why," Am. J. Phys. 76 (4), 393-399 (2008).

## Tuesday, September 7, 2010

### Pen Picture for ranking purposes

Pen Picture for ranking purposes
1.    Your achievements for the year and how your contributions have played a role in achieving the outcome of the project/task:
MOE under ETD ICT connection
•   Conceptualized, designed & wrote ICT connection and Learning Teams which achieved the one MOE discussion forum outcome for the edumall.sg discussion forums and easy access and integrated into the main page of edumall that aims to communicate to teachers and EO the spirit of working as one MOE Learning Teams.

with RVHS under Personally Motivated Project

• Co-design 2 lesson examples with Mr LEE TL  River Valley High School that aims to engage students to be SDL and CoL learners through.

with ACJC and PJC under CSCL PropelT

• Co-design physics lesson on circular motion with ACJC and gravitational field with PJC
• Finer customize each 4 simulations (total 8) to enhance inquiry approach to learning.
• Create an expert concept map to support teachers and students interaction
• Improve teacher capacity to deliver customized ICT learning
• Improve student learning using ICT ( concept map & simulations )

with 3 Primary and Ngee Ann Sec under Learning Community Study
• Glean learning points about effective formation and sustenance (nurturing) of LC through use of computer- supported communication and collaborative platforms.
Inter Divisional Committee with NIE & industry
Member of Physics taskforce committee for O and A level Physics representing ETD working with Academy of Singapore Teachers AST, NIE and industry.
• Pioneer the subject chapter of physics to enhance the technology, Pedagogy Content Knowledge (TPCK) of all O & A level physics teachers in Singapore.
•  Review and recommend ICT pedagogy framework for blended learning in physics education.
• Conceptualize, design & develop 2 lesson exemplars ( O & A Level) for effective teaching and engage learning
•    Kinematics of bouncing ball using video analysis and datalogger ICT pedagogy.
•    AC Generator using simulation and datalogger

2.    The professional sharing that you have initiated or led:

• Conducted a workshop on Video Analysis pedagogy on kinematics of bouncing ball at ICT Mentor Science Face to Face Sessions at Queensway Sec and River Valley High School  14 May & 20th May
• Conducting a workshop on Video Analysis using tracker at Science Teachers' Conference 23 & 24th November 2010 Singapore Science Centre

3.    Any other areas that you feel that you have impacted and how:

• An agent of change to lead care and inspire the teaching profession through Physics CoP.
• pursuing PhD in Physics Education on simulations for visualization of electromagnetism under Dr Jennifer Yeo and Dr Daniel Tan (NIE NSSE)
• Designing a lesson package on Electromagnetism with inputs from DET & DDPDC for consideration for system wide "scaling" to secondary schools
• Presenting in IPSG instructional support group A level physics 2011 @ACJC with RVHS, Dr Charles Chew (master physics teacher), Dr Raymond Tsoi & Dr Tan KC.
• Presenting in 4th redesigning pedagogy  on technology use in physics education 2011 with RVHS
• Write a paper with Dr Darren Wong (NIE, NSSE) and AJC colleagues on multiple representation in Physics 2011
• Design a simulation with Dr Foong (NIE, NSSE) on ball rolling down an inclined plane.
• Attend conference MPTL International Conference on Multimedia in Physics Teachings and Learning in Europe and AAPT American Association of Physics Teachers in USA, meeting and value add to the Open Source Physics community like Dr Francisco Esquembre, Dr Wolfgang Christian, Dr Fu-Kwun Hwang, Dr Frank F. Schweickert, Dr Doug Brown, Dr Bruce Mason and many more.

## Thursday, September 2, 2010

### Physics Task Force Committee PTFC for O and A level Physics

Physics Task Force Committee PTFC for O and A level Physics from 1st July 2010 to 31st March 2011.
Charles_Chew@moe.gov.sg
chewmingkheng@gmail.com
Wee_Loo_Kang@moe.gov.sg
weelookang@gmail.com
raymond.tsoi@nie.edu.sg
Something i learn from this task force.
Send a proper letter through Principal or Director, this gets recognition for job scope, the loosely bind interest subject based community can exist better when the organization acknowledge it as work.
Quite a few people are intrigue by the letter, just thought it is okay to share it right? Any copyright infringements?

This task force is definitely the best working committee i am in. Everyone is in it on their own free will, all have a significant role to play, the discussion is synergistic and everyone is an expert in their own field. Thanks to Charles for heading this team.
The 2 lesson examples are:
Tracker Free Video Analysis & Modeling Tool by Douglas Brown

Blended with Real Life Data Logger Setup by AdeStation
focusing on secondary and JC level kinematics of a bouncing ball

Ejs Open Source Alternating Current Generator Model Java Applet ( AC Generator ) AC Generator
Blended with Real Life Data Logger Setup by AdeStation
focusing on secondary and JC level electromagnetism of a AC generator

Exciting stuff by Dr. KC Tan
DataLogger by ADDeSTation courtesy of Dr kctan, founder
Real Life setup of a electromagnetic induction setup, courtesy of Dr kctan, founder
Real Life setup of a AC generator  setup, courtesy of Dr kctan, founder