Here are some Java applets that give you a chance to explore some scientific principles the same way a professional scientist does: by messing around with a system that exhibits the principle. The main difference is that these systems are all simulated -- they exist only on your computer. But they are quite realistic, in the sense that their properties are calculated carefully by accurate and modern scientific methods. Indeed, simulations such as these form an important modern scientific research tool.

In order to use any applet you must have a browser that supports Java applets. Netscape Navigator 2.0+ and the Sun HotJava browser support applets.

Each applet comes with instructions and commentary. In most cases you will be able to play with the simulated system by fiddling with its parameters. Experiment!

The Happy Molecules

A demonstration of the illusory nature of irreversibility. No controls here. But fun.

Chemical Kinetics Simulation

A simple simulation of a binary chemical reaction. You can control the initial concentrations and the chemical reation rate constants. You get a live picture of the reaction and, if you like, a ticker tape showing the concentrations moment by moment.

The Second Law

A simulation of a bouncing, heatable box that illustrates dramatically The Second Law of thermodynamics (the one about entropy). By manipulating the parameters of the simulation you can illustrate a number of fundamental facts about energy flow. (New and improved!)

The Ideal Atmosphere

A simplified simulation of the Earth's atmosphere illustrates the canonical ensemble and the Boltzmann distribution.

The Particle in the Box

A classic quantum mechanics problem. You can alter the box in the middle to move smoothly between the regular square well to the double square well with whatever barrier height and width you choose. Energies and wavefunctions calculated while-you-watch.

The Monte Carlo Polymer

An illustration of Monte Carlo computer simulation in the context of a simple model of flexible polymers.