At the heart of Molecular Workbench’s modeling of atomic interactions is a profoundly important but fundamentally simple concept: At close distances, atoms attract each other until they get so close that they repel
Here’s a demo of that concept: two atoms interacting. Drag the red atom to various locations near and far from the white atom and watch what happens as the two atoms approach each other and move apart. (If you’re wondering why the atom slows down and stops, the answer is that we apply an artificial damping force to the green atom in order to make it easier for you to “grab” it and play with it.)
Explore how the volume of a gas affects pressure.
Gases can be compressed into smaller volumes. How does compressing a gas affect its pressure?
Run the model, then change the volume of the containers and observe the change in pressure. The moving wall converts the effect of molecular collisions into pressure and acts as a pressure gauge. What happens to the pressure when the volume changes?
All molecules attract to each other, but there are different patterns and strengths of attraction that occur. The model below shows a bunch of polar and non-polar molecules.
Explore how different or similar molecules form intermolecular attractions when they are close together.
There is a weak attraction between all atoms and molecules called London dispersion. Polar molecules additionally attract via dipole-dipole attractions. Together, the London dispersion and dipole-dipole attraction are what we call intermolecular attractions.
In the previous model, time was standing still, so you could explore when intermolecular attractions form. In this model the molecules will be allowed to feel those attractions and move accordingly. Use the model below to explore the differences in the strength of London dispersion and dipole-dipole attractions for molecules of similar size.
It is well known that "oil and water don't mix", but why is that the case?
The model below shows polar water and non-polar oil in a container together. Press "run" to see how they interact.
Salad dressing is typically made from oil and vinegar (primarily water). Use the button below to "shake up the dressing" and watch what happens to the oil and water as you let it "settle".
The model below has two tiny drops of liquid, one polar and the other non-polar. By heating up these liquids you can vaporize them (or boil them), causing the molecules to break free of their intermolecular attractions. You know that something has been vaporized when most of its molecules have broken free of their attractions. Pressing the heat and cool buttons will change the temperature of these liquids.
Try heating the liquids slowly to see which one will vaporize first.
This Interactive includes a graph of Kinetic, Potential and Total Energy.