Notes on simulations developed by John Clement.

John is a long-time physics modeler in Houston. John earned a Ph.D. and has extensive career experience in the private sector. He is an avid reader of physics education research, and he has done considerable action research in his classroom, and given presentations on it at AAPT meetings and conventions of other professional societies.  – Jane Jackson


Date:    Sat, 17 Sep 2016

From:    John Clement <clement@HAL-PC.ORG>

Subject: Simulations


Due to changes in my ISP, I had to move my simulations and simulation links to:


The direct link is


I had to revise a number of them to make them work on the new host.  So it is possible that your favorite may not work.  Please let me know which ones are broken or missing.


These are modeling-friendly in that they do not give the theory, and are suitable for exploration and paradigm labs.  Some physical labs take a long time, but since these simulate physical labs, you can cut the time for the lab work.  It is recommended that you show then a physical setup of the same situation during the initial concrete preparation brainstorm.


There is some evidence that simulations may work marginally better.  For example they found that students using circuit simulations could wire up a circuit faster than students who did equivalent activities with physical equipment.



Date:    Fri, 30 Sep 2016

The simulations at  http://jclement.altervista.org_Simulations_science.htm

Should now all be operational except for some which are not under my control.  Some links to outside simulations are not correct.  The simulation of mixing colored light was kindly supplied by another person and needs to be changed to be in line with current Java standards.  It can be run if added to the Java exception list.


I have tested them on both Firefox and Internet Explorer.  Some of them do not work well when first started.  You may have to click reset or run, then reset.  It is my impression they are buggier under Firefox, but they work with IE.  They have also been tested on a Mac and seem to run OK there.  


The MOP simulations may be missing pictures on some computers or browsers.  They work OK with IE under Windows 7 and 10.  This is a problem that has not been solved yet!


My original ISP stopped supporting user web sites and wiped them all out.   The rest of my original web page is a bit of a mess, but pieces of it have been moved elsewhere.  The new web site does not properly handle either spaces or underscores in the names, so I had to make wholesale changes.  It is possible that some of my simulations have not been properly renamed, so please let me know if any particular favorite can not be accessed.



Date:    Sat, 8 Oct 2016

From:    John Clement <clement@HAL-PC.ORG>

Subject: Java Simulations


While I have put JAVA simulations on the web, everyone should be aware that

they may have problems, depending on the web browser.  JAVA is undergoing a

severe makeover and the usual way of creating applets is going away.  Rather

than fixing the security, the developers are essentially trashing useful

tools.  The developers of Physlets are busy changing the code so it will

work with the current standards, but the browsers may implement changes

before the new code is complete.  Currently Internet Explorer seems to work

best, and Firefox is usable on Macs.  But Firefox is spotty on Windows and

Chrome is reputed to not work at all.  Edge reputedly doesn't support Java.


 I will attempt to go with the flow and fix things as problems are found, but

I can't always beat the game.  I have fixed some links and have modified

some of my simulations to be more friendly to older standard definition

displays.  In particular, the cart on ramp simulations should work better

with older displays that are not wide screen.  However, a scrolling

problem is present in all Java.  If you scroll, the Java pictures are

messed up.  Most of my simulations do not need scrolling for 1080 vertical

displays.  The workaround is to refresh the browser.  The sliding controls

usually work either for full scrolling to the top or bottom.  Messed up

graphs/pictures are restored by reset or start.


 Other Physlets by the developers also have similar problems, so this is not just my problem.


Nov. 10, 2016

I have updated the gravitational force simulation.

1.  It should have all controls visible, even for a non-widescreen projector/display.

2.  It has direct readount of the distance between the masses, and the force

The gravitational simulation is at the bottom of the page.


Finding the force by measurement is a bit too time-consuming, and now students cannot make a mistake if the test mass is moved up or down.


The data should look better.  (Also, in the previous version the only way to figure the force was to measure the length of the arrow.  This causes problems with students who do not understand negative/positive.  When the arrow crosses over zero and they click on the ends to find the length, they can get a negative and a positive number.  Then then subtract them incorrectly by not noticing that one of them is negative.)


However, I have encountered a problem with this simulation on Firefox on a Mac that is set to non-widescreen mode.  The numbers inside the slider readout boxes are enlarged, which truncates the exponent readout.  Students can click on the number and then scroll the number, but they may not be aware of this.  On my computer, one must click reset to display the distance and the force initially.  However, when the mass is first moved, the data is displayed even if reset is not used.


This simulation is quite suitable for modeling the general gravitational force in a paradigm lab.  Since this can not be modeled with a real physical lab, the simulation lets the students explore how this force works, both inside and outside the planet.  The concrete preparation text explains that one can put the test mass inside the planet.  When students click run, they think they are seeing it orbit the planet.


Since there is data that shows simulations work as well as, and sometimes better than, physical labs, we should not be afraid to use them.  They save time which can then be used to tackle other problems.  In particular, some of the PHET simulations are very good for modeling.  The ladybug circular motion simulation is very good, and also the piston simulation is wonderful for tackling the gas laws.  Students do not associate the modeled gas laws with what they have been told in chem until you write the final equation in the standard chem form.  Supplementing the ladybug simulation with some simple physical examples of circular motion is helpful.  For example, kick a bowling ball (or a basketball very gently) to get it to go in a circle.  The bowling ball and broom or rubber mallet is very good.