[quote author=Fu-Kwun Hwang link=topic=1526.msg5786#msg5786 date=1270775677]
Ejs and tracjer both using open source physics library. They use data analysis tool to do similar job.
Run ejs in application mode (i.e. double click downloaded jar file).
Right click in the simulation region, then select "elements options",
and you will find options to show data in table or analyse data.

However, the data has to be predefined.

For example: if you have trace in plottingpanel show (x,y) trace point for a particle,
you will be able to find table for x,y
But EJS can not tell you the period even the above trace is a circle.
However, if you can tell the time step, student can count the number of step in the table for a complete circle motion to find out the period.
[/quote].
I understand :) so it is actually inside Ejs already as Data Analysis


[quote author=Fu-Kwun Hwang link=topic=1526.msg5786#msg5786 date=1270775677]
You will need to have r,t  trace in plottingpanel to display table for r,t
and ask students to find out the period from the table.

It is depends on how you use it to guide student to investigate those variables available in EJS model.

[/quote]

Yes it seems the plot shall be r vs t, to allow students to determine r mean through Data Analysis , mean or straight line fit for the y-intercept

The period T needs to be read off by observation of the 3D view, i could also provide the data as hints in the applet if need.

after this, they move on to Google Fusion Table http://tables.googlelabs.com/Home?pli=1 and analyse the table data of
r mean and T
from which with some copying and modifying
hopefully
T^T vs r*r*r is achieved.


i think i got it pretty much like that, where students engage in the practise of science discovery!
Anything to add?

Thanks!