Seeing Abstractions: Link Roundup

By Benjamin Senzer

Though abstract concepts are central to many areas of science and mathematics, it can be difficult to visualize them. One of the best ways to do so is by physically interacting with these ideas using models. The following online applets allow users to play with models to learn more about the scientific principles behind the universe in which we live.

Wave applet

When most people think of waves, they think of the ocean waves they see when they go to the beach. But there are many important kinds of waves, from the light waves that allow us to see to the sound waves that allow us to hear. Explore the different properties of waves using this applet.

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Orbital applet

Every physical object in the universe is composed of incredibly small particles called atoms. In turn, these atoms are composed of even smaller particles called electrons, which move around a small unit in the center of the atom called the nucleus. The 3-dimensional area around the nucleus in which electrons are most likely to be found is called an orbital. Use the applet below to view the complex shapes of orbitals for different kinds of atoms.

Gas applet

Particles of gas—from steam to the air we breathe—behave in very interesting ways when subjected to different conditions, such as changes in volume, temperature, and pressure. Use this applet to see how gas particles move in different environments.


Cycloid applet


If you were to trace the path of a single point on the edge of a rolling circle, you would end up with a very special curve known as a cycloid. Cycloid curves are often used in architecture to create very stable archways for buildings. The applet below allows you to trace out cycloids from different sizes of circles.

Natural selection applet

Evolution takes place when an individual organism has some genetic mutation which allows this organism to have a greater chance of survival than the rest of the population. This advantageous mutation is then passed on for generations until a large proportion of the population has the mutation. This applet simulates how a population of organisms changes when mutations occur.

Polypeptide applet

Proteins in our body are made of long molecules called polypeptides. Polypeptides have a very distinct chemical structure that allow them to fold into proteins that perform many important tasks in every cell of our body. Look at the atoms and distinct 3-dimensional structure of polypeptides with this applet.

Stars applet

Humans are most familiar with one particular star in the sky—the sun. However, in our galaxy alone, there are billions of stars, some orders of magnitude larger than our sun and millions of miles away from the Earth. Use this applet to explore the vast number of stars in our neck of the Milky Way Galaxy.


Gravity applet

Gravity is the force that attracts two different objects based on their mass and distance apart from each other. Gravity is responsible for keeping every physical object on Earth from floating weightlessly in space. This applet allows you to see how gravity forces certain objects to orbit around larger objects, similar to how the moon orbits around the Earth.