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Java Applets for High School and College Physics Education

Ekim 6, 2006 11:33 · Kategori: Uncategorized

Brigham Young University

Department of Physics & Astronomy

Java Applets for High School and College Physics Education
Awards and Citations.

Please use Netscape Navigator or Communicator 3.01 or later !
Not all applets are guaranteed to run on Microsoft Internet Explorer.

Animations

Transverse and Longitudinal Waves

Animation of transverse and longitudinal wave motion.

Molecular Model of a Gas

Animation of molecular model of a mixed gas.

Brownian Motion

Animation depicting Brownian motion of a large particle in a sea of smaller particles.

Wave Interference ?

Interference of two sinewaves.

Doppler Effect ?

Animation of the Doppler effect for a moving source.

Relativistic Light Clock ?

Animation of a light clock, demonstrating time dilation for moving clocks.

Relativity of Simultaneity ?

Special relativity and simultaneous events.

Single Slit Diffraction ?

Animation of single slit diffraction.

Double Slit Wave Interference ?

Animation of interference pattern formed by two slit diffraction.

Bohr Model of the Atom ?

Animation of a simplified Bohr atom with emission of photons.

Bohr Model of the Atom, Absorption and Emission ?

Animation of a simplified Bohr atom with absorption and emission of photons.

Double Slit Electron Interference ?

Animation of interference pattern formed by electron two slit experiment. Illustrates dual wave-particle behavior of electrons.

Radioactivity ?

Animation of the decay of a radioactive element. Illustrates the remaining number of undecayed atoms in time.
Presentations

Colors and Light

Color addition and subtraction.

Distance vs. Displacement

Demonstrates the difference between distance and displacement.

Vector Addition

Vector addition and vector components.

Projectile Motion

Depicts V, V_x, V_y, and A for an object in projectile motion.

Force Diagrams and Newton’s 2 ^nd Law

Exercise in constructing a force diagram.

Newton’s 3 ^rd Law ?

An interactive quiz on Newton’s 3^rd Law.

A Simple Pendulum

A simple model of a simple pendulum, illustrates period vs. length.

A Mass on a Spring

A simple model of a mass on a spring, illustrates displacement vs. velocity vs. acceleration.

Damped Oscillator

A mass on a spring with damping.

The Continuity Equation

An animated presentation illustrating the continuity equation.

Ideal Gas Law, Pressure vs. Volume

Model of an ideal gas with constant temperature.

Ideal Gas Law, Pressure vs. Temperature

Model of an ideal gas with constant volume.

Electric Field between 2 Charges

Models the Electric Field between two charges, one charge is variable.

Series Approximation

Series approximations using Fourier and Lengendre series.

Series Approximation

Series approximations using Fourier and Lengendre series.
Simulations

Refraction of Light

Simulation of refraction and change of wavelength and wavespeed.

Thin Lens

Simulation of convergent and divergent lens.

Thin Lens and Mirrors

Simulation of convergent and divergent lens and mirror.

Author:Phillip R. Dukes

To obtain copies of any of these applets for use in physics education, please write to:

dukesp@physics1.byu.edu
Brigham Young University
Provo, UT

Acknowledgments: Many of these applets were developed with the support of a grant from the Utah State Higher Education Technology and Distance Education Initiative. The Java video applets were developed with the support of a grant from the Brigham Young University Faculty Center. Thanks also go to Prof. Dorian Hatch, Physics Department Chair, for his support and helpful comments with the development of these applets and his assistance with editing the digitized videos. document.write(”

This page was last updated on ” + document.lastModified);

This page was last updated on 10/06/2006 11:31:42

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Signals Systems Control

Ekim 6, 2006 11:32 · Kategori: Uncategorized

Johns Hopkins University		Signals Systems Control

	Joy of Convolution A Java applet that performs graphical convolution of continuous-time signals on the screen. Select from provided signals, or draw a signal with the mouse. Includes an audio introduction with suggested exercises and a multiple-choice quiz. (Prepared by Steven Crutchfield, Fall 1996.)
	Joy of Convolution (Discrete Time) A Java applet that performs graphical convolution of discrete-time signals on the screen. Select from provided signals, or draw a signal with the mouse. Includes an audio introduction with suggested exercises and a multiple-choice quiz. ( Original applet by Steven Crutchfield, Summer 1997, is available here. Update by Michael Ross, Fall, 2001.)
	Interactive Lecture Module: Continuous-Time LTI Systems and Convolution A combination of Java Script, RealAudio, technical presentation on the screen, and Java applets that is used at Johns Hopkins to complement classroom lectures on the discrete-time case. (Applets by Steven Crutchfield, interface by Mark Nesky, Spring 1998.)
	Fourier Series Approximation A Java applet that displays Fourier series approximations and corresponding magnitude and phase spectra of a periodic continuous-time signal. You can select from provided signals, or draw a signal with the mouse. ( Original Applet by Steven Crutchfield, Fall 1996, update by Hsi Chen Lee Summer, 1999.)
	Listen to Fourier Series Sound generated by Java applets is used to introduce basic notions of Fourier series, including harmonic content and filtering. (Prepared by Michael Ross, Spring 2004, based on an earlier version by Kevin Rosenbaum, Fall 1995.)
	Interactive Lecture Module: Harmonic Phasors and Fourier Series Java applets, a technical presentation on the screen, and RealAudio provide an interactive introduction to continuous-time phasors, rotating vectors in the complex plane. Phasors are used illustrate basic characteristics of Fourier series, including convergence properties, Gibbs effect, and windowing. (Applets by Hsi Chen Lee, Winter, 1999) This is based on an earlier demonstration using .mpeg movies developed by Nabeel Azar, Spring 1996, and available here. Included in this earlier version is a downloadable M-file for interactive Matlab execution. These efforts are motivated by the 1971 movie Harmonic Phasors II, by William H. Huggins.
	Phasor Phactory For the phasor phanatic, this applet that offers 4 ways to generate and observe continuous-time harmonic phasor sums and the corresponding Fourier Series. (Prepared by Hsi Chen Lee, Winter, 2000)
	Continuous Time Fourier Transform Properties Displays the effect various operations on a continuous-time signal have on the amplitude and phase spectra of the signal. Presentation MathML is used to display equations and Content MathML, JavaScript, and a Java applet provide live updates of Fourier transform magnitude and phase expressions. Requires Microsoft Internet Explorer 5.5+ with MathPlayer plugin. An earlier version that does not use MathML, is more portable, and includes a larger collection of signals is available here. (Prepared by Michael Ross, Winter 2002, Spring 2003.) An even earlier demonstration on similar material, prepared in 1996 by Christopher Hocker, is available here.
	Discrete Time Frequency Includes a Java applet for exploring the notion of frequency for discrete-time signals. You can specify the frequencies of two discrete-time phasors and produce the corresponding real and imaginary parts for comparison. Includes a quiz. (Prepared by Andrea Dunham, Summer 2001.)
	Discrete-Time Fourier Series Presentation MathML is used to display equations and Content MathML provides an expression of the discrete-time Fourier series that interacts with a Java applet to explore periodic signals with period N = 5. A second applet can be used to explore signals with longer period. Requires the Microsoft Internet Explorer 5.5+ with Math Player plugin. (An earlier version of the demonstration that does not make use of MathML features and is compatible with other browsers can be found here.) For signals with period N = 5, enter the magnitude and phase spectra or the signal with the mouse. Or enter coefficients in the mathematical expression for the Fourier series. Then select play to observe the individual frequency components in the complex plane and the sum of these components. A second applet handles signals with periods up to N = 32, but does not display the mathematical series or the individual frequency components. Audio clips and suggested exercises are included. (Prepared by Lan Ma and Michael Ross, Summer 1999, 2002.)
	DTFS Properties A Java applet that displays the effect that various operations on an N-periodic, discrete-time signal (e.g. time shift, time scale, filtering) have on the signal and its spectra. The user sketches the signal or the spectra with the mouse and then selects the operation. (Prepared by Lan Ma, Winter 2000.)
	Discrete-Time Fourier Transform Properties A Java applet that displays the effect that various operations on a discrete-time signal have on the amplitude and phase spectra of the signal. (Prepared by Lan Ma, Summer 2000.)
	SampleMania A Java applet for signal sampling at various sampling frequencies, and signal reconstruction from samples using various low-pass filter cutoff frequencies. Select from provided signals, or draw a signal with the mouse. This demonstration labels frequency in units of radians per second, click here if you prefer Hertz. (Prepared by Steven Crutchfield, Spring 1997.)
	System Properties The user applies input signals to a selected, unknown system - either continuous time or discrete time - to determine whether the system is linear, time invariant, causal, stable, and memoryless. (Prepared by Raman Venkataramani, Summer 1996.)
	LTI Arcade A Java applet that invites the user to select an LTI system, sketch an input signal with the mouse, and observe the output signal in real time. Output targets can be set and the miss distance will be computed. (Currently runs on MS Internet Explorer.) (Prepared by Seth Kahn, Winter, 2000.)
	Exploring the s-Plane A Java applet where the user can drag poles and zeros around the s-plane and observe changes in the unit-step response of the corresponding linear dynamic system. Includes an audio introduction with suggestions. (Prepared by Brian Woo, Fall 1997.)
	Bode Servo Analysis A Java applet for control systems. Drag open-loop corner frequencies with the mouse to improve tracking performance and reject sensor noise in a unity-feedback system. (Prepared by Steven Crutchfield, Summer 1997.)
	Bode Servo Analysis (Time Delay) A modification of Bode Servo Analysis for control systems with time delay (transport lag) elements included in both the forward and feedback paths. (Prepared by Seth Kahn, Spring 1998.)
	Sense and Sensitivities A Java applet that illustrates the utility of the sensitivity and complementary sensitivity functions for linear control system design. Sketch a reference input and disturbance input with the mouse, and select a sensor noise level. Then drag open-loop system poles and zeros with the mouse to track the reference while rejecting the disturbance and noise. Includes an audio introduction with suggested exercises. (Prepared by Seth Kahn, Winter, 1999.)

These demonstrations were developed in a project directed by Wilson J. Rugh to explore the use of the World Wide Web in engineering education. New demonstrations are added and existing demonstrations are updated on a regular basis. Further details about the beginning of the project can be found in a now somewhat dated paper. A recent paper describing our efforts with MathML is here.All the demonstrations work as designed on MS Windows with the current version of Internet Explorer. With Netscape or Mozilla there are occasional problems in the appearance of equations or in the layout or execution of applets. On Unix or Apple computers, these problems are more frequent and more severe. RealAudio clips in the demonstrations require the free player available at http://www.real.com. Narration on several demonstrations is by Cherie Weinert.

Support from the National Science Foundation, and the Kenan Fund, the Center for Educational Resources, and the E.J. Schaefer Chair at Johns Hopkins is gratefully acknowledged.

This site was selected as the Premier Engineering Courseware of 2001. Details available here. Congratulations to all the students who have worked on the demonstrations!

Please visit also the Java-based Virtual Engineering/Science Laboratory by Michael J. Karweit at Johns Hopkins.

Comments are welcome via email to the individuals cited above or to Wilson J. Rugh.
(Page design by Mark Nesky, Summer 1998.)

Applets and lecture modules listed below are under construction and are offered on an “as is” basis. They may be incomplete in various ways, they have not been thoroughly checked for technical accuracy, and appearance may be rough.

Robust Stabilization A killer applet for the Robust Stabilization Theorem of linear control theory. Enter a nominal plant P(s), and specify an uncertainty weighting function W(s) by dragging poles and zeros with the mouse. Then design a unity-feedback compensator C(s) by dragging poles and zeros to achieve closed-loop robust stability. Includes a Fine Print document that references further information about the theorem and outlines calculations supporting the applet. (Prepared by Steven Crutchfield, Winter, 2000.)

Copyright 1995-2002, Johns Hopkins University and Wilson J. Rugh, all rights reserved. Visitors are permitted to access this site for personal or non-profit educational use only. Copying or duplicating the images or code is prohibited. Use of this site for business or commercial purposes also is prohibited.

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