Java Applets

Linear Regression Fitting and Graphing Programs

Linefit Script. Note: If your browser doesn't run java applets well, then click on: Linefit Script for a javascript version of linefit. You should be able to run this on your phones.

Linefit was written by Cal Poly Computer Science students Joel Onofrio and Kiet Tran. Enter the "x" and "y" values for your data, and the program will plot the data, find the slope and intercepts. The program will also find the uncertainties in these values. You can also change which data is used in the "linear regression fit". Netscape 4.08 or better or IE 4.0 or better is need with this applet.

FitIt was written by Cal Poly Computer Science Student Liz Reznak (Sp 2006). It is an improvement of linefit that includes semi-log and log-log fits as well as some polynomial forms. This work was made possible by the WEEA professional development program.

Photon Interference Applet

The Photon Interference Applets below were written by Cal Poly Computer Science students as part of Dr. Sang's CS480 class. The applets simulate the arrival of photons on a screen after traveling through either one or two slits.

photon interference was written by Cal Poly students Matt Henderson, Chang Kim and Jason Kang. Just choose the number of windows (or screens) and use the task bars.

photon interference applet was written by Cal Poly students Brian De Wolf, Vern Jensen and Juan Pastor.

Oscilloscope Simulator

The oscilloscope simulator programs below were written by Cal Poly Computer Science students as part of Dr. Sang's CS356 class. They are designed to help students in first year physics classes learn how to determine the frequency and amplitude of a signal on an oscilloscope. Note: you might need to a more recent version of Java for your browser. The applets work with IE 6.02 or better.

oscope was written by Cal Poly students Michael Lee, Benjlyn Lopez and Pascal Huoth. This version has "sliders" along the axis to allow the user to move the signal around. Click "randomize" a few times to get a nice signal. Note, the nice help box.

Oscilloscope was written by Cal Poly students Erik Waibel, James Wong, Devin Smith and Phan Su. This applet doesn't have sliders, but it works very well, and is a good version to start with. There is also a help box.

oscilloscope was written by Cal Poly students Wei Zhao, Mark Soriano and Mihn Truong. This version was the first to use "sliders" to move the signal around. It is well written and simple to use.

RPN Calculator

RPN Calculator is a Reverse Polish Notation calculator written in javascript, that displays four stack levels. It is small enough to fit on a netbook, templet, or phone. The javascript source code is: RPN source

Central Force Program

Central Force was written by Cal Poly Computer Science students Tam Ho, Quan Le and Trung Tran. This applet plots the motion of a planet which experiences the force F = - Kr^n . The default values are for the inverse square force: n = -2. Change the exponent in the force law, and investigate the planetary orbits.

Alkali Energy Level Programs

alkali2 was written by the student group led by Anh Mach. It can run with Netscape 3.0 or better.

alkali1 was written by the student group led ty Xiong (Sean) Lin. It can run with Netscape 4.5 or better.

How to use the Alkali Energy Level Programs

The program calculates the energy levels for the valence electron for the alkali elements. Pick an element from the box. Pick a value of the parameter c (Angstroms). Then click on calculate, and wait for the calculation to finish. First the experimental values of the energy levels (in eV) for the l=0, l=1, and l=2 levels are printed, Then the calculated values are computed and printed. Vary the parameter c (Angstroms) for the best fit to the experimental values.

The program calculated the energy levels as follows: It is assumed that the valence electron experiences a "mean field" potential, V(r), due to the nucleus and the other electrons. The potential V(r) is inserted into the Schroedinger equation, and the code solves Schroedinger's equation for the bound states. The potential V(r) is taken to be the sum of a potential due to a point charge (the nucleus) of magnitude +Ze and a screening potential due to the other (Z-1) electrons in the atom. The screening potential is that due to a uniformly charged sphere of radius c and total charge of -(Z-1)e.

There is a translation of this page in Danish. All links to translations have been removed.

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