## Thursday, June 10, 2010

### Ejs open source java applet 1D collision carts Elastic and Inelastic Collision « on: December 23, 2008, » posted from:Singapore,,Singapore

 http://weelookang.blogspot.com/2010/06/ejs-open-source-java-applet-1d.htmlhttps://dl.dropbox.com/u/44365627/lookangEJSworkspace/export/ejs_Momentum1D2010web04.jarauthor: lookang and paco Thanks To Professor Fu-Kwun Hwang for guidance and Professor Francisco Esquembre for EJS and the open source digital library source codes

virtual laboratory simulation for One Dimension collision of two carts allowing inquiry learning for elastic and inelastic studies.
Thanks To Professor Fu-Kwun Hwang for guidance and Professor Francisco Esquembre for EJS and the open source digital library source codes.

http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=831.30

YouTube. Was stuck at Portland airport from 11pm to 4am, decided to use the time to make some promotional video on the applets shared during 2010 AAPT Summer Meeting in Portland, Oregon

Momentum One Dimension Collision Model

The motion of a body of mass m and velocity v is described by a vector quantity known as momentum p where

p = m v

When objects collide, whether trains, cars, billiard balls, shopping carts, or your foot and the sidewalk, the results can be complicated. Yet even in the most chaotic of collisions, as long as there are no net external forces acting on the colliding objects, one principle always holds and provides an excellent tool for understanding the collision. That principle is called the conservation of linear momentum which states that

The total momentum of a system remains constant provided that no external resultant force acts on the system

For two bodies colliding linearly, it is written mathematically as a vector equation

Total initial momentum = total final momentum

m1.u1 + m2.u2 = m1.v1 + m2.v2

If external forces (such as friction) are ignored, the total momentum of two carts prior to a collision (left side of equation) is the same as the total momentum of the carts after the collision (right side of equation).

Collisions are classified into elastic (or perfectly elastic), inelastic and completely inelastic.

There is also a concept of kinetic energy of a moving body is stated mathematically by the following equation:

KE1 = ½ m1.v12

Main Simulation View
The simulation has 2 collision carts on frictionless floor and wheels.
Sliders

Explore the sliders allows varying the variables .

* mass of cart ONE, mass_1, m1 in kg
* initial velocity of cart ONE, u1 in m/s
* mass of cart TWO, mass_2, m2 in kg
* initial velocity of cart TWO, u2 in m/s

Allows for selecting what kind of collision is simulated.

A Perfectly elastic collision is defined as one in which both conservation of momentum and conservation of kinetic energy are observed
A Perfectly Inelastic collision is defined as one in which conservation of momentum is observed but the colliding carts stick together after collision with kinetic energy loss

Checkboxes
show: velocity, for visualizing the velocity vector
plot momentum vs time graph, for different representation of data for momentum of cart 1, 2 and both.
plot kinetic energy vs time graph, for different representation of data for kinetic energy of cart 1, 2 and both.
paused when collide, for visualizing the change in the velocity u1 and u2 to v1 and v2
fast simulation, for cases where the velocity are low and repeat learners can spend time more usefully collecting and analysing data.
hint: COM, for the equation of conservation of momentum
hint: COKE, or the equation of conservation of kinetic energy

Buttons
Play
Step Back
Step Forward
Initialize
Reset
have their usual meaning.
known bug is the Step Back button implementation, please fix it if you can and email me the improved source XML.

Credits:
The Momentum 1D Collision model was created by created by lookang using the Easy Java Simulations (EJS) version 4.2 authoring and modeling tool. An applet version of this model is available on the NTNU website . Shout our thanks to the Ejs community namely, Francisco Esquembre , Fu-Kwun Hwang and Wolfgang Christian for their professional learning community support. You can examine and modify this compiled EJS model if you run the model (double click on the model's jar file), right-click within a plot, and select "Open EJS Model" from the pop-up menu. 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/

Some demonstrations of various types of collsions along a low friction track.

Dynamics
Linear momentum and its conservation

(g) state the principle of conservation of momentum.
(h) apply the principle of conservation of momentum to solve simple problems including elastic
and inelastic interactions between two bodies in one dimension. (Knowledge of the concept
of coefficient of restitution is not required.)
(i) recognise that, for a perfectly elastic collision between two bodies, the relative speed of
approach is equal to the relative speed of separation.
(j) show an understanding that, whilst the momentum of a system is always conserved in
interactions between bodies, some change in kinetic energy usually takes place.
http://www.seab.gov.sg/SEAB/aLevel/syllabus/2010_GCE_A_Level_Syllabuses/9646_2010.pdf

the video to share the message of using virtual lab to learn by doing.

this video was made to share some implementation tips and best practices and of course students feedback that affirms the learning strategy through virtual lab pedagogy.
enjoy!

Write up

Lesson Idea Synopsis

A co-created virtual lab learning environment was designed with guided discovery worksheets to support the process of sense making of the physics of collisions. Students investigated into the relationship between the variables collaboratively in groups of 2 to 3, and also shared their analysis through short presentations, for other students to critique.
http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=831.0

Instructional Objectives

Candidates should be able to:
1. apply the principle of conservation of momentum to solve simple problems including elastic
and inelastic interactions between two bodies in one dimension.
2. show an understanding that, whilst the momentum of a system is always conserved in
interactions between bodies, some change in kinetic energy usually takes place.

How was the lesson carried out? (Please include level, ICT equipment & resources needed, pedagogy or strategies used, thinking skills taught, if any, duration of lesson, etc)
Self-directed learning (SDL)
Ownership of Learning, students set and identify variables to inquiry on, for example, mass (m1 and m2), initial velocity (u1 and u2), type of collisions (perfectly elastic, partially elastic and perfectly inelastic). Learners have to decide type of variables to inquiry, for example, momentum, kinetic energy, relative speed of approach and separation etc.
Management and Monitoring of own Learning, students explore experimental data and make logical arguments and findings.
students formulate questions and generate own inquiries when conducting the virtual experiment guided by the worksheets.
Students use the feedback form to improve their experience in using the virtual lab.
Extension of Own Learning
Apply learning in new contexts is supported by the application worksheet where they conduct a problem based learning scenario of a crash site between a lorry and a car by examining the evidences of skid marks on the road etc.
Learn beyond the curriculum, students are expose to the concept of coefficient of restitution, e and getting a larger schema of the equations of collision taught in university courses.

Collaborative Learning (CoL)
Effective Group Processes, in pairs the students need to negotiate and set common goals to explore in the lab
Individual and Group Accountability of Learning, students learn in pairs, share their findings in short oral presentations, supported by peers evaluation.

The lesson was carried out with year 5 (JC1),
ICT equipments used included Computers, with Java Runtime installed, Ejs open source java applet 1D collision carts Elastic and Inelastic Collision 1mb file copied into the desktop.
Pedagogy is Learner centred learning with technology.
Strategies Teacher as technology, content, pedagogy and knowledge expert (TPCK), facilitating the inquiry learning process, with teacher to facilitate at suitable times.
Thinking skills, Self directed planning of inquiry approach is required for students to collect data, Science Practical Assessment Skill A. Analysis of data skill is also practiced. Evaluation of data and finally Synthesis skill during the proposing and verifying of their hypothesis of the physics principle .
Lesson is 1 hour 40 mins

How did ICT value-add to the learning process? How did the use of ICT change the learning and teaching process?
1. safe inquiry, lesser chance of injury during physics practical as there is no physical objects moving or falling off apparatus etc.
2. easy setup with virtual labs, real life setup is difficult to calibrate the motion sensors, lack of sufficient number of practical sets
3. 1 to 1 exploration of science principle
4. time spent on learning increased, less time spent on debugging the real life data logger setup with connecting wires, faulty sensors, inaccurate data collected, less variables can be varied reliably.
5. support any time ( no restricted to that practical lesson ), any place ( home based lessons is possible)

What were the outcomes? (Benefits to pupils or teachers, re-designing of pedagogy, development of staff, etc)
Benefits to students as collected in the feedback forms are
Yes Hands-on learner
Yes Autonomy to try out different situations
Yes Learn better and clearer this way
Yes Instill concepts and understanding through a clear learning process
Yes See physics theory comes to life, make it easier to understand
Yes Expt is interesting
Yes Hands-on is interesting
Yes Good alternative to usual lab
Yes Fun and engaging
Yes More hands-on, better than lecture
Yes Interactivity keeps me awake
Teacher benefit is he is more convinced that he is doing something meaningful to engage his students.

Re-designing of pedagogy is still teach less, learn more (TLLM), make the learners the centre of learning activities.

Development of staff is teachers learn to design learning environments (java applets), design worksheets to implement meaningful ICT lessons.

How did you assess student's learning using ICT? (Examples of work produced, etc)
Students work were captured in the worksheet.
Students interviews indicate the ICT lesson enables them to learn on their own, more engaging than exisitng lecture style of information delivery system.
Students feedback affirmed the physics teachers professional learning community (PLC) effort.

Do you consider the ICT lesson a success? What went well? What would you do differently next time?
"More this kind of lesson
More fun activities
It's flawless
Lesson is effective enough
Lesson is well-planned and effective
Lesson was very concise and effective as it is
Less amount of trials should be conducted
Quite effective"
Differently, Students suggested that
"Air-con room keeps us awake and absorb better
A little more challenge worksheet, maybe engage them in the modeling aspects of the physics or improving the worksheet.
Have better graphics
Applet could be more vivid".

What went well?
Teachers going around to help the groups of students make sense of their own inquiry on variables like real scientists.

What would you do differently?
the teachers role is critical to promote the learning and sense making process, the teacher has to go around the groups to facilitate and ask the groups to make their own logical conclusion and hypothesis.

Will you be conducting this lesson again? If so, when will it be? (E.g., Term 3 in 2010; on-going, etc)
Yes, It will be conducted yearly, usually term 1 JC1.
There is a level wide scaling and translation to all JC1 physics classes from 2010.
With this lesson example, it is hoped that all interested will use this virtual lab to impact their schools physics curriculum through technology.

on 23march 2009 in a class of 24 in a typical pre u one setting of a physics lab session 1 hr 40 mins

the data collected are as follow

I managed to meet up with my school teacher friend and got some of the student feedback forms.
i key in the data (43) / ~200 forms, the data seems to suggest it is a meaningful practical lab made possible through this applet and planning from the teachers in that school RVHS.
(63) / ~200 as of 8sept2010
Google Form which all can see, not edit

summary of results

certificate of appreciation from ICT connection CHEAH Horn Mun

Perfectly inelastic collision

Perfectly elastic collision

This example m1=1000kg, u1=5m/s, m2=0.1kg, u2=0m/s, the final velocities are approximately given v1=4.999m/s, v2=9.999m/s

contribute to Wikimedia
ThumbnailDateNameUserSizeDescription
16:39, 3 July 2011Collisioncartsm1greatergreaterthanm2.gif(file)Lookang123 KB
14:36, 2 July 2011Collision carts inelastic.gif (file)Lookang422 KB
14:36, 2 July 2011Collision carts elastic.gif (file)Lookang293 KB