Image © 2006 The Living Earth/livingearth.com

Earth and Moon Viewer

If Earth appeared like this as seen from the moon, how would the moon would appear from Earth? To find out, see Earth and Moon Viewer.

Also, check out this applet simulation of Earth, moon, and Sun, including the phase of the moon (Press the "Animate" button to start the motion, and press the same button, which will now say "Stop," to stop the motion whenever you like).

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PhET: Projectile Motion

Security note:
Once you have clicked on the "simulation" link below, be sure to read the Java Security Advisory before running the simulation: To do that, click the "Read now" button on the yellow band near the top of the PhET page.

To explore particle trajectories, try PhET: Projectile Motion for a simulation of firing various objects out of a cannon.  You can find out how the angle, initial speed, mass, and air resistance affect the path of the projectile.  This item is part of a collection of simulations developed by the Physics Education Technology project (PhET) at the University of Colorado.

(This feature was updated on May 5, 2013.)

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image credit: Magnetic Materials Center, University of Tsukuba

Evidence for Atoms

This field ion microscopy image (hi-res version) shows the arrangement of atoms in the tip of a tungsten needle. Images like this were first made by Erwin Mueller in 1951. To learn more, visit Principle of Field Ion Microscope.

Seeing may be believing, but there was considerable evidence for atoms by the middle of the nineteenth century. For the history of the idea of atoms, see  Evolution of the Atomic Concept.

Que tal in the Current Skies

The night sky is definitely "worth a look." Visit Que tal in the Current Skies for information about the visible planets, our moon and other moons, the sun, and other celestial objects.  You'll find monthly star maps, animations that show celestial motions, and more. To learn much more, you can explore Sky and Telescope's Almanac.