The Easy Java Simulations Modeling and Authoring Tool is needed to explore the computational model used in the Boston University Physics Easy Java Simulation: Electric Field in 1D.

1st remix made
Ejs Open Source Electric Field & Potential of 2 Charged Particles Java Applet by lookang.
a remix of this original model by Professor Andrew Duffy.
customized it for sg syllabus

2nd new remix is born! Re-purposed into Ejs Open Source Gravitational Field & Potential of 2 Mass Java Applet by lookang.
Many thanks to Professor Andrew Duffy for his original codes, to Professor Fu-Kwun Hwang for his forum and community of learners & to Professor Paco for creating Ejs toolkit and Professor Wolfgang for OSP codes.

3rd remix probably final one, authentic case study of a exam question scenario Ejs Open Source Gravitational Field & Potential of Earth and Moon Java Applet by lookang.
based on Real Data!
customized by lookang based on an applet by Professor Andrew Duffy.
many thanks for allowing people to learn from your codes.
OSP guys and gals are heroes in physics education :)

This applet even has activities / exercises to promote student to notice, think about the physics examined illustrated :)

An interactive tutorial on electric field, developed for high school physics by The Physics Classroom.