PhET Simulation: Geometric Optics ` - Jul 15, 2013

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.

Visit PhET Simulation: Geometric Optics for an interactive simulation from the University of Colorado on how to make images with a convex lens (like a magnifying glass).

MIT Technology Review: X-Rays Made with Scotch Tape ` - Jul 1, 2013

It's easy to produce x-rays--just unwind scotch tape (but you have to do it in a vacuum). For the next step, an x-ray image, see the video in this MIT Technology Review article.

(This feature was updated on April 26, 2014.)

What Is a Neutrino…And Why Do They Matter? ` - Jun 1, 2013

Check out this PBS webpage for an introduction to neutrinos. To learn more about the different types of neutrinos, see this University of California page.

PhET Simulation: The Greenhouse Effect ` - May 1, 2013

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.

Investigate climate change with this PhET simulation. You'll see how greenhouse gases keep Earth much warmer than it would be without them.

(This feature was updated on May 3, 2013.)

Earth Observatory: Solar Prominence ` - Apr 1, 2013

Visit Earth Observatory: Solar Prominence, and take a look at these two images of a solar prominence. How does a prominence look when you see it at the sun itself, compared when you see it against the darkness of space? When you see the prominence against the sun, it's usually called a "filament." To learn more, read the text under the images.

Kitchen Sink Experiments: Bubbles that sink: Antibubbles ` - Feb 1, 2013

Think about a bubble: It's a thin film of water, with air inside and outside. Now imagine the opposite of a bubble: That would be a thin film of air, enclosing water inside and surrounded by water outside. This structure is called an antibubble.

To learn how to make anti-bubbles, visit Kitchen Sink Experiments: Bubbles that sink: Antibubbles and also Science by Email--AntiBubbles.

To learn more, see this Science News Online article.

Spectral Lines ` - Jan 1, 2013

Auroras are produced when charged particles from the sun collide with atoms in the atmosphere and transfer energy to them. This energy is then given off as light. Check out Spectral Lines to find out how atoms produce light.

Feather Drop ` - Dec 1, 2012

Felix Baumgartner was nearly in free fall as he stepped out of his capsule at an altitude of 39 kilometers (24 miles). At this altitude, the atmosphere is so thin that a falling object experiences hardly any air resistance, so it accelerates rapidly to very high speed (Baumgartner's skydive exceeded the speed of sound).

Watch the video at Feather Drop to see how the air resistance on a feather depends on the density of the air it is falling through. First you'll see the feather fall through air at atmospheric pressure, and then through air at a very low pressure (a very good vacuum).

Liquid Crystal IR Detector ` - Nov 1, 2012

Go to Liquid Crystal IR Detector for an experiment that shows how a liquid crystal can detect infrared radiation.

How to Make a Paper Crane--Origami ` - Oct 1, 2012

Visit How to Make a Paper Crane--Origami to make the famous origami paper crane. Just follow the steps in the video.