## Wednesday, April 30, 2014

### Tracker 4.85 features demo by douglas brown

New features include
1. a translucent grid overlay, mouse control of numerical values in the model builder,
2. model "launching" with a point mass, and
3. easy font resizing for presentations or hi-res monitors
thanks professor douglas brown for creating this wonderful tool.

### Tracker: natashataiqianhui student video bouncing ball filmed horizontally by camera

natashataiqianhui

 http://weelookang.blogspot.sg/2014/04/tracker-natashataiqianhui-student-video.html bouncing ball video https://www.dropbox.com/s/vz3dbyvlvpe1m7s/natashataiqianhui_304_18_physicstrackerfamodel.trz author of video: natashataiqianhu, author of model: lookang (only for the first 3 bounces is added)

## mentoring suggestion:

good effort.
look at the TRZ file to see how scientists use models (mathematical equations to predict and explain).

question for u to think about.
1. explain what does this model do
y = if (t<0.4,0-0.75*t-5.351*t^2,if(t<1.202,-3.275+8.052*t-5.126*t^2,if(t<1.95,-12.24+15.44*t-4.962*t^2,-0.95)))
for the first three bounce.
2. after you understood point 1, can u add the 4th bounce ?
3. suggest why this is a deep way to learn physics.

enjoy!

## Explanation of the model:

kinematics model
y = if (t<0.4,0-0.75*t-5.351*t^2,if(t<1.202,-3.275+8.052*t-5.126*t^2,if(t<1.95,-12.24+15.44*t-4.962*t^2,-0.95)))

in a nested loop,
if time is less than 0.4, then y is equal to 0-0.75*t-5.351*t^2 as coefficients are determine from the data analysis power 2 fit
if time is less than 1.202, then y is equal to-3.275+8.052*t-5.126*t^2 as coefficients are determine from the data analysis power 2 fit
if time is less than 1.95, then y is equal to --12.24+15.44*t-4.962*t^2 as coefficients are determine from the data analysis power 2 fit
else don't bounce y = -0.95

## Tuesday, April 29, 2014

### Tracker: valarylim student inleastic Collision of 2 marbles on a horizontal track

helping leongster to mentor students in becoming like scientists!

 http://weelookang.blogspot.sg/2014/04/tracker-inleastic-collision-of-2.html video by valary lim, kinematics model by lookang 1. explain why the model A is written as x = if(t<0.333,0.60*t,if(t>0.333,0.1998+0.15*(t-0.333),0)) 2. explain why model B is written as x = if(t<0.333,0.205,0.205+0.44*(t-0.333+0.0333)) https://www.dropbox.com/s/4ypouk5hgc69hww/304-307valarylimmarble_analysisandmodel.trz

## Mentoring Suggestions

hi valary lim,
good effort on the video tracking.
some points to note.
1. video taking need to firm on a mount to reduce error in movement

some physics ideas for you to think about.
1. show that momentum is conserved just before and just after collision in the TRZ file i uploaded?
2. from the kinetic energies of the 2 masses (assume to be same mass for both marbles) suggest what type of collision it is? ( elastic, inelastic or partial inelastic ?)

u can refer to Mr Wee's TRZ for reference and the model A and B built inside
model thinking questions:
1. explain why the model A is written as x = if(t<0.333,0.60*t,if(t>0.333,0.1998+0.15*(t-0.333),0))
2. explain why model B is written as x = if(t<0.333,0.205,0.205+0.44*(t-0.333+0.0333))

extension problem:
1. using the acceleration graphs to estimate the average impact-contact force on marble A and B and the highest instantaneous impact-contact force.

enjoy!

## Answer to explain the model A and B

1. model A is written as x = if(t<0.333,0.60*t,if(t>0.333,0.1998+0.15*(t-0.333),0))
the syntax for kinematic model is if ( variable < value , true do this, false to that )
so t is time, so if time is less than 0.333 seconds, the model is x = 0.60*t where 0.60 is the velocity
in the nested if loop, if time is greater than 0.333 seconds, x = 0.1998+0.15*(t-0.333) where 0.1998 is the initial x position,  0.15 is the velocity and (t-0.333) is needed to make the particle model appear only after 0.333.
else x = 0 which in this model which do nothing in particular since t < 0.333 and t > 0.333 covers all time or case.

2. explain why model B is written as x = if(t<0.333,0.205,0.205+0.44*(t-0.333+0.0333))
in the same manner, if time less than 0.333, do x = 0.205 (fixed position) else do x = 0.44*(t-0.333+0.0333) where 0.44 is the velocity of mass B

### Tracker Pre-Test by leongster

Vid 1:
http://tinyurl.com/l2oyd8t

Vid 2:
http://tinyurl.com/lgrqu82

Vid 3:
http://tinyurl.com/jvmf6en

## Questions for students: https://www.edmodo.com

The video shows a ball bouncing on planet X.

The mass of the ball is 0.20 kg.

Using the video tracker software, analyze the vertical motion of the ball (horizontal analysis is not required).

Save your trk file as class_name eg. 316_leongtzekwang and submit the trk file to the edmodo assignment “tracker quiz”.

You are only required to analyze the vertical motion.

1. What is highest speed of the ball throughout the duration of the video? [2]
2. What is vertical velocity of the ball at the highest point after the first bounce? [1]
3. What is acceleration of the ball at the highest point? [2]
4. How long did the ball take to hit the floor from the time of release? [1]
5. What is the maximum acceleration of the ball during the first bounce? [2]
6. What is the maximum net force acting on the ball during the first bounce? [1]
7. What is the maximum normal contact force by the floor on the ball at the point of impact? [1]

### Invitation to Participate in Excellent Service Award (EXSA) 2014 - MOE HQ and Schools

i am have to provide 5 detailed examples of Excellent Service Award (EXSA) 2014.
 Invitation to Participate in Excellent Service Award (EXSA) 2014 - MOE HQ and Schools

1. Elvin of TPJC thank Loo Kang for providing all the lessons published in ICT connection as provide a roadmap for follow-up with the respective teachers in their school. To service the HOD ICT better, Lawrence also deleted the duplicated lesson in draft to cut the red tape required to remove the record from the teacher's end.
2. Yip Kim Wah and Aloysius Goh of AJC ask for new design features to be added to a simulation model on circular track (blogspost) with theoretical values included and ability to pause at various positions (bottom and top) and all possible scenarios involved in rolling down a circular track with projectile motion etc. They complimented on the fast development of the new features requested by them and for understanding their needs to publish the lesson on ICT connection on their own.
3. Sandra Ong from CPDD thank Lawrence for sharing the worksheets and journal paper, from which CPDD has adapted the ideas from the paper for our learning experiences in the new syllabus for A level Physics 2016. She also wanted the materials to be shared on Dropbox for ease of sharing with the CPDD-ETD-AST-schools curation project team.
4. Flora Ong and Derrick Siew of Hillgrove Secondary thank Lawrence for generous and creative sharing to enriched the schools niche area of flight and aerospace. Lawrence also prepared a series of materials for a 3 days - 3 hour workshop to teach students to "learn by coding" physics of a rocket launch. Derrick's request for a additional mass versus time and energy versus time graph has been added was added meet after a face to face meeting to discuss how to conduct the enrichment workshop for 15 students in Hillgrove secondary.
5. Chee Wah of IJC commented on the smooth running the new ripple tank computer model and requested for a bug fix on the feature of "two waves from the sources do not seem to be pi radian out of phase" and Lawrence was able to figure out the problem and rectified it. In additional, Lawrence also created a YouTube video to explain to Chee Wah how to get the 3D waves to be understood and used in order to use it effectively.
There are another early 5 that lack details.

1. Yap Kian Wee of ACJC thank Loo Kang for a series of gravity simulations, including those from a MOE HQ innergy GOLD award from a workshop Loo Kang conducted and continue to network with these teachers, building capacity with resources of the teachers.
2. Samuel Ooi of NJC thank Loo Kang for the amazing radioactivity computer model suited for his teaching and the MOE curation project supported by CPDD and ETD.
3. Lawrence Lau (HODSc) Singapore Sports School thank Loo Kang for his generosity to share with all teachers in Singapore his physics simulations, especially the 2014 newly created mobile device enabled computer models.
4. Daniel Kwok of Jurong JC thank Loo Kang for the well designed simulations.
5. Kuek-Neo Yng Yng of Millennia Institute thank Loo Kang for creating simulations that have "graphics do look striking and easier to follow than some others I've seen on the internet".

## Monday, April 28, 2014

### NIE Seminar by Igal Galili

there could be 2 interesting talk that i can attend.
thanks to
hyeeun.z@nie.edu.sg and alphonsuswong@gmail.com for hosting!

NIE Seminar
1. Cultural Content Knowledge (CCK) of Physics and its impact on Teaching Physics
[PDF]
CULTURAL CONTENT KNOWLEDGE –
openjournals.library.usyd.edu.au/index.php/CAL/article/.../5966/6528‎
Date: 6th May2014 (Tuesday)Time: 1.30p.m to 3.00p.m
Venue: NIE7-01-708

Abstract.

Physics knowledge, as a subject matter of a regular curriculum, is often presented as an amalgam of topics backing in various physics theories (classical mechanics, thermodynamics, electromagnetism, relativity, quantum mechanics) without recognizing this fact and the different and often mutually contradicting conceptual basis of the knowledge elements. Physics knowledge emerges, thus, all inclusive, as if a homogeneous framework, despite the inherent conceptual incoherence. Moreover, physics curriculum often ignores any but unique account for a particular concept. I will argue that this content does not adequately represent physics knowledge, is often ineffective and suggests an alternative organization - a cultural one. The latter might be presented as a family of epistemologically similar fundamental theories. Each theory may be organized in a triadic structure: nucleus (basic principles), body (elements derived from the nucleus), and periphery (elements contradicting the nucleus) (Tseitlin & Galili, 2005). I will exemplify implications of this organization to physics curriculum, representation of conceptual change taking place in individual learner, as well as in scientific community, and to the new taxonomy of cognitive preferences of physics learners. The latter rejects the C.P. Snow's (1961) model of two cultures. I will also mention the learning materials – excurses to several physical concepts - created by our group in Jerusalem within the European developmental project HIPST (2008-2010).

NSSE Seminar
2. Providing Cultural Content Knowledge in a summative lecture - the first experiment with high school students
Date: 7th May 2014 (Wednesday)
Time: 1.30p.m to 3.00p.m
Venue: NIE7-03-109 (NSSE Journal Room)

Abstract. Argument for making physics curriculum cultural, that is, representing cultural content knowledge (CCK) cannot ignore the question regarding practical ways towards adoption of such curriculum. CCK curricular orientation presumes developing new learning materials and modifying teacher training (in particular, including history and philosophy of science). These activities are time consuming processes and should be considered as a gradual change. As a first step, we suggest a special kind of introductory teaching in the form of summative lecture. A special study was performed with regard to the knowledge of light – optics, intensively learned in high schools. This knowledge, arranged in three basic theories, the theory of rays (geometrical optics), the theory of waves (physical optics) and a theory of photons (modern physics) was reviewed in a special summative lecture following regular teaching. We made an experiment of such teaching - a lecture and a following class discussion - in three classes of Italian high school for students gifted in science (Lyceo Scientifico). I will depict the nature of the teaching content of such lecture and some findings in the analysis of lecture impact on the students and teachers of these classes. The results were promising and indicated several benefits of this type of pedagogy in providing students with a big picture of physics knowledge, its ontology and epistemology - the issues seldom addressed in regular teaching. This makes the summative lecture attractive regardless the change of the curriculum in general.

## Information about Professor Igal Galili

Igal Galili is a professor of science education at the Amos de-Shalit Science Teaching Center in the Faculty of Mathematics and Natural Sciences of the Hebrew University of Jerusalem, Israel. His Ph.D. is in theoretical physics from Racah Institute of Physics at the Hebrew University. His research interests include the structure of students’ knowledge of physics (expressed in terms of scheme-facets of knowledge), as well as the structure and nature of physics knowledge where he uses the framework of discipline-culture. He argues for representation of physics knowledge to the learners as organized in terms of fundamental theories establishing a conceptual discourse. When the subject matter includes the conceptual discourse of alternative accounts it becomes cultural in the specific sense which considers the system of knowledge as a culture. Cultural content knowledge (CCK) makes explicit the essential role of the history and philosophy of science as providing a necessary foundation for meaningful learning and understating of physics. Among his products are an introductory course of optics using CCK approach, Fundamentals of Physics and Modern Physics for school students in Israel. Several historical excurses to the conceptual history of some physical concepts were produced within the European project HIPST and published in the collection The Pleasure of Understanding.

If you are like to join us in any of these seminars, please send an email to Eugene (eugene.lim@nie.edu.sg) with an indication of the title(s) by 30 April.

### Tracker FAQ for students and teachers by tzekwang.leong@rgs.edu.sg

Learning Point of Performance Task by Leong Tze Kwang tzekwang.leong@rgs.edu.sg
thank bro for sharing

Q1: When I shift-click on the object, it doesn’t track.

A1: Just left click on Object A and try again. If everything fail, save your file and restart tracker.

Q2: When I analyzing my graph by double clicking it, it looks like a line (or a dot).

A2: It was zoomed in too much. Simply right click (double click track pad) on the graph and choose auto scale.

Q3: My acceleration graph is super messy even though it’s supposed to be constant acceleration.

A3: The acceleration is derived from the velocity, which is in turn derived from the displacement you clicked. Any error in clicking is magnified. Using the gradient of the velocity-time graph (using the best fit function) to find the average acceleration is more reliable.

Q4: I saved my tracker file (.trk) but when I open it it’s blank.

A4: Instead of double clicking to open the tracker file, drag the trk file into the tracker software.

Q5: I opened the tracker file but there’s no video.

Q5: Simply drag the video file into the tracker. The trk file and the video file need to be saved in the same folder for the tracker to find the file. Any movement of the files will need to be manually linked by dragging the file into tracker.

Q6: My video has some skip frames or repeated frames.

A6: Different camera record video at different frame rate (some camera can set the frame rate). Using a software to trim the video often results in changing the frame rate. It’s best that you use the original video but only track the duration of interest by setting the starting and ending frame instead of using another software to trim the video.

Q7: My ball (or whatever object) looks like a line instead of a ball.

A7: Most low end camera (such as phone camera) are not suitable for capturing high speed motion. Simply track the middle of the elongated object. For futther improvement, use a better camera such as DSLR camera or the Photonics high speed camera (Set it to 120 FPS). Improving the lighting (such as shooting under bright sunlight at 12 pm) will also improve the video quality.

### xmphysicdemo by Chua Kah Hean chuakh@hci.edu.sg

thanks to chuakh@hci.edu.sg for sharing his wonderful video to teach anyone Physics! hopefully i can use as much of his insights in a MOE publication http://ictconnection.moe.edu.sg/masterplan-3/i-in-practice

## Author:

Chua Kah Hean chuakh@hci.edu.sg

## What

xmphysicdemo is a youTube channel that features videos of physics demonstrations related to A-level Physics.

## Why

Usually, a live demonstration is the best. But a filmed demonstration does have many advantages over a live one.

### Slow motion

Many physics phenomena happen so fast our brains cannot register the event. High speed video is very helpful in these situations.

AC light: http://youtu.be/SpkVFRJbBTo

### Annotations

Sometimes, all it takes is a few lines added through video editing to turn an ordinary video into an insightful one.

Projective motion: http://youtu.be/Wxw2GY804t4

### Music

Some demonstrations are more enjoyable and impactful with background music.

Water fountain: http://youtu.be/hSX3T6MjL9s

### Size issues

Many small size demonstrations are unsuitable for lectures because audience seated far away cannot see the necessary detail. Filming and playing the demonstration on the big screen solves the problem.

Tuning fork: http://youtu.be/LkORKcK6yVY

### Logistical issues

Videos allow demonstrations involving heavy and bulky equipment to be brought to classrooms easily.

Magnetic force: http://youtu.be/8J86xsjjMw8

### Demo on demand

Let’s face it. Many schools are well equipped with demonstration sets that are under-utilized due to various reasons. Demonstrations videos, on the other hand, are accessible to a global audience round the clock.

## How

### Media resource for lectures or tutorials

Demonstration on video are very effective resources for daily lessons. Many demonstrations are good triggers for discussion and teaching of new concepts.

### Inquiry learning

What do we get when we pair URLs to videos of physics demonstrations, and well-designed probing questions? An inquiry learning worksheet.

## Find out more from his website

http://xmphysicsdemo.wordpress.com/

Enjoy!

### Open source physics specialist sharing with ETD

 Open source physics specialist sharing with ETD
Open source physics specialist sharing with ETD. #edsg #physicsed http://www.slideshare.net/lookang/open-source-physics-specialist-sharing-with-etd
 Open source physics specialist sharing with ETD
 http://www.opensocietyfoundations.org/explainers/what-open-access
 http://weelookang.blogspot.sg/p/physics-applets-virtual-lab.html

## Wednesday, April 16, 2014

### jan 2014 contact teacher's digest out

jan 2014 contact teacher's digest out! the article is actually about #edsg twitter as an online space for educational discussion in SG.

http://www.moe.gov.sg/corporate/contactprint/pdf/contact_jan14.pdf
 jan 2014 contact teacher's digest pg 17 Tips on building a learning  network online  http://www.moe.gov.sg/corporate/contactprint/pdf/contact_jan14.pdf

 jan 2014 contact teacher's digest pg 17 and 18 Tips on building a learning  network online  http://www.moe.gov.sg/corporate/contactprint/pdf/contact_jan14.pdf

## Speakers:

Mr. Hisham Haslir, Ping Yi Secondary School
Mr. Kwan Tuck Soon, Rulang Primary School

### EJS Dynamics: 1 Direction Collision Force Model

thanks to mr yip's feedback, a bug (solver defaulted to Euler instead of  Runge-kutta 4) was removed.

some of useful features include

for an expanded view or close up view of the F-t graph, move the carts by dragging on the carts near to the right side of the world view, as the plot detects the Tmax for simulation to run.

 collision cart, showing ideal e=0 and smaller view space xmin=0 and xmax=1 http://weelookang.blogspot.sg/2014/04/ejs-dynamics-1-direction-collision.html https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejs_model_Momentum1DForceModel09.jar author: lookang, paco and engrg1 worksheets by (lead) AJC: https://www.dropbox.com/s/5obo5awn3w3zrgr/CollsionCartsAJC.zip (lead) RVHS: https://www.dropbox.com/s/8bq51hqa1jsjcvn/CollsionCartsRVHS.zip IJC https://www.dropbox.com/s/ztwc4pkvtc7ho50/CollisoncartsIJC.zip SRJC: https://www.dropbox.com/s/m4yrerc97fgesn2/CollisioncartsSRJC.zip YJC: https://www.dropbox.com/s/uguy3ewndj0pqxr/CollisionCartsYJC2013.zip

## ideal e=1

 collision cart, showing ideal e=1 http://weelookang.blogspot.sg/2014/04/ejs-dynamics-1-direction-collision.html https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejs_model_Momentum1DForceModel09.jar author: lookang, paco and engrg1 worksheets by (lead) AJC: https://www.dropbox.com/s/5obo5awn3w3zrgr/CollsionCartsAJC.zip (lead) RVHS: https://www.dropbox.com/s/8bq51hqa1jsjcvn/CollsionCartsRVHS.zip IJC https://www.dropbox.com/s/ztwc4pkvtc7ho50/CollisoncartsIJC.zip SRJC: https://www.dropbox.com/s/m4yrerc97fgesn2/CollisioncartsSRJC.zip YJC: https://www.dropbox.com/s/uguy3ewndj0pqxr/CollisionCartsYJC2013.zip

## ideal e=0

 collision cart, showing ideal e=0 http://weelookang.blogspot.sg/2014/04/ejs-dynamics-1-direction-collision.html https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejs_model_Momentum1DForceModel09.jar author: lookang, paco and engrg1 worksheets by (lead) AJC: https://www.dropbox.com/s/5obo5awn3w3zrgr/CollsionCartsAJC.zip (lead) RVHS: https://www.dropbox.com/s/8bq51hqa1jsjcvn/CollsionCartsRVHS.zip IJC https://www.dropbox.com/s/ztwc4pkvtc7ho50/CollisoncartsIJC.zip SRJC: https://www.dropbox.com/s/m4yrerc97fgesn2/CollisioncartsSRJC.zip YJC: https://www.dropbox.com/s/uguy3ewndj0pqxr/CollisionCartsYJC2013.zip

## real e=1

 collision cart, showing real e=1, select slow?==true and data analysis of $\int F dt = \Delta Momentum$ http://weelookang.blogspot.sg/2014/04/ejs-dynamics-1-direction-collision.html https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejs_model_Momentum1DForceModel09.jar author: lookang, paco and engrg1 worksheets by (lead) AJC: https://www.dropbox.com/s/5obo5awn3w3zrgr/CollsionCartsAJC.zip (lead) RVHS: https://www.dropbox.com/s/8bq51hqa1jsjcvn/CollsionCartsRVHS.zip IJC https://www.dropbox.com/s/ztwc4pkvtc7ho50/CollisoncartsIJC.zip SRJC: https://www.dropbox.com/s/m4yrerc97fgesn2/CollisioncartsSRJC.zip YJC: https://www.dropbox.com/s/uguy3ewndj0pqxr/CollisionCartsYJC2013.zip

 collision cart, showing real e=1, select slow?==true and data analysis of $\int F dt = \Delta Momentum$ http://weelookang.blogspot.sg/2014/04/ejs-dynamics-1-direction-collision.html https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejs_model_Momentum1DForceModel09.jar author: lookang, paco and engrg1 worksheets by (lead) AJC: https://www.dropbox.com/s/5obo5awn3w3zrgr/CollsionCartsAJC.zip (lead) RVHS: https://www.dropbox.com/s/8bq51hqa1jsjcvn/CollsionCartsRVHS.zip IJC https://www.dropbox.com/s/ztwc4pkvtc7ho50/CollisoncartsIJC.zip SRJC: https://www.dropbox.com/s/m4yrerc97fgesn2/CollisioncartsSRJC.zip YJC: https://www.dropbox.com/s/uguy3ewndj0pqxr/CollisionCartsYJC2013.zip

## real e=0

 collision cart, showing real e=0, select slow?==true graphs showing some tension reaction after initial first compression http://weelookang.blogspot.sg/2014/04/ejs-dynamics-1-direction-collision.html https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejs_model_Momentum1DForceModel09.jar author: lookang, paco and engrg1 worksheets by (lead) AJC: https://www.dropbox.com/s/5obo5awn3w3zrgr/CollsionCartsAJC.zip (lead) RVHS: https://www.dropbox.com/s/8bq51hqa1jsjcvn/CollsionCartsRVHS.zip IJC https://www.dropbox.com/s/ztwc4pkvtc7ho50/CollisoncartsIJC.zip SRJC: https://www.dropbox.com/s/m4yrerc97fgesn2/CollisioncartsSRJC.zip YJC: https://www.dropbox.com/s/uguy3ewndj0pqxr/CollisionCartsYJC2013.zip

mr yip old version of my model does not really simulate the Force-time graph at collision as i used a cheating method to trick the dt to be sizeable for a detectable F-t graph but the problem is when the collision is ideal, the dt is actually zero as the computational method brings the 2 masses together at precisely the exact time, making dt =0 for calculation of Force infinity.

older version:

## lookang Digital Library of EJSS models.

thanks to +Lye Sze Yee @engrg1 for hosting my digital library of models that run on EJSS App Reader.
Get the Pro version to open unlimited number of models like I have!.
add the URL to the library.
http://iwant2study.org/lookangejss/

## Setup your own EJSS Digital Library

u need this file,https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/indexEJSSdl.php/indexEJSSdl.php or http://iwant2study.org/lookangejss/indexEJSSdl.php
http://iwant2study.org/lookangejss/

Enjoy!

3. You should be able to view the new library models on the left panel and the sub-folders models arranged in coordinated in the syllabus of O and A level.

 Paying EURO 1.99 or SGD 3.45. Worth it! support Open Source Physics work please!

Instructions of use for the Android version of the EjsS Reader App

## iOS versions on Apple’s App Store

EjsS Reader App Free on AppStore coming soon…
EjsS Reader App Pro on AppStore coming soon…

Instructions of use for the iOS version of the EjsS Reader App

## Friday, April 11, 2014

### Innergy commendation award 2014 for primary school resources

Thanks @engrg1 for your kind leadership to provide teaching and learning resources made in easy java simulation!
 Director Educational Technology Division Innergy commendation award 2014 for primary school resources by +Lye Sze Yee
Enjoy!
 Innergy commendation award 2014 for primary school resources by +Lye Sze Yee
 Innergy commendation award 2014 for primary school resources by +Lye Sze Yee

## Tuesday, April 8, 2014

### EJSS Static and Kinetic Friction on Incline Plane Model

EJSS Static and Kinetic Friction on Incline Plane Model

reference:
1. EJS Static and Kinetic Friction on Incline Plane Model by Francisco Esquembre and lookang http://weelookang.blogspot.sg/2014/04/ejs-static-and-kinetic-friction-on.html
2. Sliding Down an Incline Plane Model by Francisco Esquembre http://www.compadre.org/osp/items/detail.cfm?ID=9973
 EJSS Static and Kinetic Friction on Incline Plane Model http://weelookang.blogspot.sg/2014/04/ejss-static-and-kinetic-friction-on.html https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejss_model_friction/friction_Simulation.html source: https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejss_src_friction.zip author: Francisco Esquembre and recreated on EJSS by lookang
 EJSS Static and Kinetic Friction on Incline Plane Model http://weelookang.blogspot.sg/2014/04/ejss-static-and-kinetic-friction-on.html https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejss_model_friction/friction_Simulation.html source: https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejss_src_friction.zip author: Francisco Esquembre and recreated on EJSS by lookang

 EJS Static and Kinetic Friction on Incline Plane Model http://weelookang.blogspot.sg/2014/04/ejs-static-and-kinetic-friction-on.html https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejs_model_SlidingDownAnInclinedPlanewee.jar author: Francisco Esquembre and remixed by lookang

## Model description by Paco:

### Block sliding down an inclined plane

A stone block is lying on an inclined plane.

Initially, the component of gravity along the plane surface, $mg cos (\theta ) = F_{tangent}$ , is balanced by the force caused by static friction $f_{static}$, which is proportional to the normal to the plane, $N$ .
The model assume the mass of the block is m = 1 kg,

$W = mg$

where $W$ is the weight and $g$ is the gravitational constant of 9.81 m/s^2

In equilibrium,

$\sum F = 0$

$mg sin ( \theta ) - f_{static} = 0$

$mg cos ( \theta ) - N = 0$

In this model,

$F_{tangent} = mg sin ( \theta )$

$F_{normal} = mg cos ( \theta )$

However, the modulus of this force $f_{static}$ cannot exceed a limit value of  $\mu | N|$  where $\mu_{static}$ is the static friction coefficient between the block and the plane.

$f_{static} \leq \mu_{static}N$ in the direction negative of the velocity vector.

In this model, when velocity = 0,

$f_{static max} = \mu_{static}N$ and

$f_{static } = -Math.min( mg sin( \theta ), f_{static max} )$

since $f_{static }$ cannot be greater than $mg sin( \theta )$ nor $\mu_{static}N$

When the user increases the slope of the plane $\theta$ by dragging slider of angle $\theta$ , $F_{tangent}$ ends up being larger than this limit and the block slides down the plane with kinetic friction present $f_{kinetic} = \mu_{kinetic}N$ .

In this model, when velocity not equal to zero,

$f_{kinetic} = - \mu_{kinetic}N$ .

The force caused by static friction is replaced by a (smaller) force of dynamic (or kinetic) friction $f_{kinetic}$, given by $\mu_{kinetic} |N|$ (where $\mu_{kinetic}$ is the dynamic friction coefficient between the block and the plane, which is smaller then the static one, $\mu_{static}$).

## Condition for hint:

if (velocity = 0 and and only and totalForce(t,x,v) = 0), hint statetext = " in equilibrium,..."
else if (velocity = 0 and and only and totalForce(t,x,v) != 0) hint statetext = " NOT in equilibrium,..."
else if (velocity != 0) hintstatetext= " NOT in equilibrium and in motion..."

## Determine direction of motion and direction of friction

if (v===0){
directionOfMotion=0;
}
else if (v<0){
directionOfMotion=-1;
}
else if (v>0){
directionOfMotion=+1;
}

## Custom function:

function totalForce(time,position,velocity) {
if (velocity!==0) return Ft+directionOfMotion*dynamicFriction; // in motion
return Math.max(0,staticFriction+Ft); // not in motion
}

1. re-implemented on EJSS
2. added a scaleforce to draw the forces to user's choice
3. made the static and kinetic friction drawn from same vector as visible===true was buggy
4. added more hints to make explicit in equilibrium and not in equilibrium when net force.
5. made the color dynamic with change in static to kinetic
6. added paco as co-author as the EJS codes came from the man :)

## Monday, April 7, 2014

### Tracker video analysis and model on elastic collision

Tracker video analysis and model on elastic collision.
video by Joel A. Bryan http://jabryan.iweb.bsu.edu/videoanalysis/index.htm
for more video go to Video Analysis: Real World Investigations for Physics and Mathematics by Joel A. Bryan.
model by lookang
Model B: if(t<0.5, 0.673*t, 0.02*(t-0.5)+0.34)
Model C: if(t>0.5,0.586*(t)+0.223,0.5)

 http://weelookang.blogspot.sg/2014/04/tracker-video-analysis-and-model-on.html Tracker video analysis and model on elastic collision. video by Joel A. Bryan http://jabryan.iweb.bsu.edu/videoanalysis/index.htm model by lookang https://dl.dropboxusercontent.com/u/44365627/TrackerDigitalLibrarySG/Tracker%20RVHS/elastici.trz Model B: if(t<0.5, 0.673*t, 0.02*(t-0.5)+0.34) Model C: if(t>0.5,0.586*(t)+0.223,0.5)

As a response to Samuel's question, we did this in 2010 as a tracker analysis for RVHS students and we speculate model building strengthens learning.

enjoy!

## Friday, April 4, 2014

### EJS Static and Kinetic Friction on Incline Plane Model

EJS Static and Kinetic Friction on Incline Plane Model

reference:
1. Sliding Down an Incline Plane Model by Francisco Esquembre http://www.compadre.org/osp/items/detail.cfm?ID=9973

 EJS Static and Kinetic Friction on Incline Plane Model http://weelookang.blogspot.sg/2014/04/ejs-static-and-kinetic-friction-on.html https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejs_model_SlidingDownAnInclinedPlanewee.jar author: Francisco Esquembre and remixed by lookang

## Model description by Paco:

### Block sliding down an inclined plane

A stone block is lying on an inclined plane.

Initially, the component of gravity along the plane surface, $mg cos (\theta ) = F_{tangent}$ , is balanced by the force caused by static friction $f_{static}$, which is proportional to the normal to the plane, $N$ .

In equilibrium,

$\sum F = 0$

$mg sin ( \theta ) - f_{static} = 0$

$mg cos ( \theta ) - N = 0$

However, the modulus of this force $f_{static}$ cannot exceed a limit value of  $\mu | N|$  where $\mu_{static}$ is the static friction coefficient between the block and the plane.

$f_{static} \leq \mu_{static}N$

When the user increases the slope of the plane $\theta$ by dragging the double arrow at the plane top, $F_{tangent}$ ends up being larger than this limit and the block slides down the plane with kinetic friction present $f_{kinetic} = \mu_{kinetic}N$ .

$f_{kinetic} = \mu_{kinetic}N$ .

The force caused by static friction is replaced by a (smaller) force of dynamic (or kinetic) friction $f_{kinetic}$, given by $\mu_{kinetic} |N|$ (where $\mu_{kinetic}$ is the dynamic friction coefficient between the block and the plane, which is smaller then the static one, $\mu_{static}$).

1. re-position to the hint texts
2. made the hint "change the angle of the slope and click play" to appear once only and playing and paused as other hints
3. re layout the model with my usual slider design and colored background
4. added stroke line to be dashed to represent components of gravity forces
5. made the auto-scale of y to allow angle up to 90 degrees.
6. added a scaleforce to draw the forces to user's choice
7. made the view xmin,xmax, ymin,ymax to increase by 1 if object over move
8. fix a bug on the visual of vector of kinetic friction to be directionOfMotion*dynamicFriction

### Modelling Instruction in Singapore

Thanks to Darren and colleagues in Curriculum and Planning Division (CPDD) Ministry of Education (MOE) and National Institute of Education (NIE), Modelling Instruction is slowing but surely getting more attention in Singapore as an viable active learning pedagogy for Physics Education.

update: 6 june 2014

Dear Participants,
I am pleased to inform you that the course “Modelling Instruction in Physics Workshop (1ST Run)” has been confirmed.
Please find the details of the course as follow:
Dates: 8 & 9 Jul 2014
Time: 9AM- 5PM
Venue: NIE7-B1-22

Points to note:
1. Tea-break will be provided for the course duration. All foods are served halal.
2. You are advised to bring a sweater as the room may be cold.
3. If you are unable to make it for the course, please send a replacement from your school. Do inform me of the replacement’s name, so that changes can be made accordingly.

Thank you and have an enjoyable and fruitful time at the course!

E-register [1st Run] successful.  8 & 9 Jul
E-register [2nd Run]

What is Modeling? from MVP Studios on Vimeo.

## Modelling Instruction in Physics Course Synopsis

The course will introduce teachers to a model-centred, guided-inquiry method to teaching Physics based on a Modeling Theory of Physics Instruction, which has been the focus of educational research by David Hestenes from Arizona State University and collaborators since 1980. The name Modeling Instruction expresses an emphasis on making and using conceptual models of physical phenomena as central to learning and doing science. Specific examples will illustrate how this method of instruction can increase conceptual understanding and develop scientific views of Physics.

## Who Should Attend

Upper Secondary/IP Physics teachers

## Details

Date : 8-9 July 2014 (1st run) , 10-11 July 2014 (2nd Run)
Time : 9 am - 5 pm
Venue : TBC

## Course Objectives

This course is designed for teachers to:

1. experience the use of Modeling Instruction in Physics to teach electricity and magnetism concepts
2. experience the use of whiteboarding and Socratic dialogues to improve scientific discourse in the classroom
3. network with other fellow educators keen on the Modeling approach in order to share ideas and to support each other in implementing it in the classroom

## Course Outline

The course focuses on key concepts in Electricity and Magnetism from a model-centered perspective. Participants will work through examples from a microscopic perspective to develop a deep understanding of content and how to teach it effectively. They will experience the use of multiple representations (verbal, diagrammatic, graphical and algebraic) as conceptual tools for modeling physical objects and processes. They will also experience the use of whiteboarding as a tool to improve the quality of classroom discourse.

## Course Content

Overview of Models and Modeling
1. Electric charge and electric fields
2. Electrical energy and electric potential
3. Electric current (surface charge model)
4. Magnetic fields and forces
5. Electromagnetic induction

## Fee

MOE participants - $225.70 (incl. 7 % GST &$1 Copyright Fee)

Non MOE participants – $974.70 (incl. 7 % GST &$1 Copyright Fee)

## Closing Date for Applications

6 June 2014
Applicants will be notified of the results of their applications via e-mail.

## Email

You have registered for Modeling Instruction in Physics
Session Date: 8 & 9 Jul
Salutation : Mr
Name : wee loo kang lawrence
Email : wee_loo_kang@moe.gov.sg
Contact : 92475573
Registration ID : 739774
Event Venue: TBC
Event Date (Start): 08 Jul 2014 09:00 AM (End): 09 Jul 2014 05:00 PM

### Overcome the Java Web Signature by adding exception site list

But my Java applets http://weelookang.blogspot.sg/p/physics-applets-virtual-lab.html should not have these difficulties as in my Open Source Physics work, I normally allow you or anyone to download them as run locally in your hard drive.

Having said that, the new JavaScript models http://weelookang.blogspot.sg/p/a-new-page-for-all-ejss-javascript.html has and will continue to be runnable with no security threats associated to Java runtime on the web deployed mode.

1. visit the website with the java applets you wish to explore for example http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=692.0
2. click on and go to your Java Control Panel by navigating to Start Menu, Control Panel and click on the Java icon to run the Java Control Panel (note it requires Java runtime update 51 to have this feature)
3. click on the Security Tab and add the website URL (the root form as that everything hosted on that URL will work in the future) for example http://www.phy.ntnu.edu.tw/ntnujava/ by clicking on the Edit Site List Button and Add the website URL.
4.  Agree to the security risk and click continue
5. Your favourite Java web-deployed website works now like a charm
6. Enjoy!