Explore the role of charge in interatomic interactions. The forces attracting neutral atoms are called Van der Waals attractions, which can be weak or strong, depending on the atoms involved. Charged atoms (also known as ions) can repel or attract via Coulomb forces, and the forces involved are much stronger. Oppositely charged atoms attract to each other, while similarly charged atoms repel. The attractive forces between atoms have consequences for their interactions in physical, chemical and biological applications.

Move point charges around on the playing field and then view the electric field, voltages, equipotential lines, and more. It's colorful, it's dynamic, it's free.

This resource consists of a Java applet and expository text. The applet simulates the chuck-a-luck experiment of rolling 3 fair dice. The random variable of interest is the net profit of the player.

This resource consists of a Java applet and expository text. The applet is a simulation of the experiment that consists of tossing a coin and then rolling either a red die or a green die, depending on the outcome of the coin toss. The probability of heads and the distributions of the two dice can be specified. The applet illustrates a two-stage experiment.

This resource consists of a Java applet and expository text. The applet simulates coin tosses. The number of coins and the probability of heads can be varied.

Explore the energy exchange between colliding objects and observe how energy transfer occurs under various circumstances.

Investigate the difference in attractive force between polar and non-polar molecules by 'pulling' apart pairs of molecules. While all molecules are attracted to each other, some attractions are stronger than others. Non-polar molecules are attracted through a London dispersion attraction; polar molecules are attracted through both the London dispersion force and the stronger dipole-dipole attraction. The force of attractions between molecules has consequences for their interactions in physical, chemical and biological applications.

Investigate the difference in attractive force between polar and non-polar molecules by "pulling" apart pairs of molecules. While all molecules are attracted to each other, some attractions are stronger than others. Non-polar molecules are attracted through a London dispersion attraction; polar molecules are attracted through both the London dispersion force and the stronger dipole-dipole attraction. The force of attractions between molecules has consequences for their interactions in physical, chemical and biological applications.

Compare the change in potential energy when you separate molecules from each versus when you break molecules apart.

Students compare slope as it relates to distance vs. time. Using a simulation on Desmos, students find that faster speeds create steeper slopes on a graph.

Before Ernest Rutherford's famous gold foil experiment in 1911, it was not known how the positive part of the atom was distributed. His experiment showed that if you shot positively charged particles at the atoms in a very thin sheet of gold foil, that very rarely, a particle would bounce back from the foil rather than going straight through it. Experiment with changing the distribution of positive charge and see how it affects the paths of positively charged particles moving near it.

The heat conductivity of a solid material defines how fast heat will flow through it. You can probably think of several everyday examples of materials with high (fast) conductivity or low (slow) conductivity. This model illustrates the effect of different conductivities by placing different materials between a hot and a cold object and graphing the changing temperatures.

The rate of heat flow between two objects is proportional to their difference in temperature. One experiences this every day, with stoves, outdoor weather and touching things. If you touch something that's the same temperature as your hand, there's no heat flow at all. This model allows you to adjust the temperature difference between two objects and observe the graph of heat flow.

Heat flows through solids at rates measured by their conductivity. The rate of heat flow is also proportional to the thickness of the material. This model compares the rate of heat transfer between two objects when they are separated by walls of different thickness.

Experiment with conductivity in metals, plastics and photoconductors. See why metals conduct and plastics don't, and why some materials conduct only when you shine a flashlight on them.

If there are air leaks in a house, you might expect that their effect would be magnified on a windy day. The wind creates greater air pressure on the windward side of the building and forces air in through the leaks. At the same time, the pressure on the other side of the building is lowered, pulling air out through leaks. This model has a fan blowing against a building. Air motion is shown with arrows. Open and close the "windows" in the building and observe the results.

Convection refers to transfer of heat by a fluid material (such as air or water) moving from one place to another. The convection is forced if the fluid motion is caused by a fan or a pump while natural convection is the result of density differences.

Conduction of heat refers to the transfer of heat through a solid. Convection refers to the transfer of heat by a fluid material (such as air or water) moving from one place to another. Warm air is less dense than cold air, so it rises and cold air sinks. This is called natural convection. Air is constantly circulating indoors and outdoors, moving heat from one place to another. With this model you can compare how conduction and convection transfer heat.