August 1, 2006 Issue

Physics To Go 6 - Sun time/anti-particle

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Physics in Your World

The Analemma image
image copyright: Dennis di Cicco/Sky and Telescope; larger image

The Analemma

The photo shows a series of images of the sun photographed at the same time of day for a year. This pattern, called the analemma, results from both the elliptical orbit of Earth and the tilt of its axis. For more information, visit The Analemma.

Also, to see similar analemmas photographed at various times of day above Greece temples, go to the Stanford Solar Center. And to make an analemma on a globe, see the Analemma Project activity.

This feature was updated on July 2, 2009.

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Physics at Home

Colored Shadows

Try this Exploratorium activity to explore colored shadows. With red, green, and blue light bulbs, you'll cast shadows with interesting colors (one, when the blue light is blocked, is quite a surprise!). To investigate the colors in white light, visit another Exploratorium activity, How to Build a Spectroscope!. Be sure to do this project with the supervision of an adult.


From Physics Research

The First Antiparticle image

The First Antiparticle

photo from Physical Review 43, 1034 (1933)

This photograph (hi-res version) provided evidence for the existence of antimatter. The curved track was made by a positron –the antiparticle of the electron--moving in a magnetic field. Note the change in curvature where the particle passed through a lead plate (seen edgewise in center). To learn more about interpreting this photo, see The First Antiparticle from Physical Review Focus. To find out more about antimatter, visit Antimatter, from CERN.

Worth a Look

A Visual Interpretation of the Table of Elements

Visit A Visual Interpretation of the Table of Elements for a novel periodic table that combines art and science with an icon for each element, based on its properties and its role in technology and culture. The site provides information about each element.

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