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In this issue:
Update: Suspicious Packages
Safety Today: How do Smoke Detectors Work?
Stanford Art Gallery Presents "Sliding Scale"
Safety Second

SLAC Today

Tuesday - November 7, 2006

(Image - envelope)

Update: Suspicious Packages

Two weeks ago, the arrival of a letter containing white powder at Lawrence Berkeley National Laboratory prompted the SLAC directorate to advise all staff to be particularly careful of suspicious or unusual mail. Fortunately, lab tests revealed that the Lawrence Berkeley letter contained nothing more than harmless powder. Nonetheless, SLAC employees and users are encouraged to use caution when opening unexpected packages.

The SLAC directorate has released new guidelines on what to do if you suspect you have opened a package containing harmful substances.  Please take a few moments to read these guidelines here.

(Column - Safety Today)

How do Smoke
Detectors Work?

Daylight Saving Time provides a convenient reminder for people to change the batteries in their smoke detectors. But how do smoke detectors work in the first place?

The most common type of detector contains americium, which slowly releases alpha particles. These particles ionize the oxygen and nitrogen atoms in the air, releasing a free electron and a positively charged atom. Inside the detector, free electrons are attracted to a metal plate with a positive voltage and the positive atoms are attracted to a plate with a negative voltage. Electronics in the detector sense the very small electrical current created by this movement.

When smoke enters the detector, the current disappears as the smoke particles attach to the ions and neutralize them. The detector recognizes this and the alarm goes off.

A second type of detector uses light to detect the smoke. In this case, a beam of light shines across the inside of the detector. When no smoke is present, the photons travel in a straight line, missing a sensor placed to the side. But if smoke enters the detector, the photons bounce off the smoke particles and send light in all directions. This light is then detected by the sensor, and the alarm goes off.

To learn more about the physics of smoke detectors, visit How Stuff Works.

Safety Seconds

In yesterday's edition, I noted that if you look at all the injuries suffered by SLAC staff members, you find at least two common patterns. The first is that almost all were engaged in activities that they understood and were quite familiar with. The second is that the staff member was nearly always not thinking about accident prevention in the seconds before his or her injury.

Stanford Art Gallery Presents "Sliding Scale"

(Photo - artwork by Gail Wight)
Gail Wight's Supernova
(Click on image for larger version.)

Today, the Stanford Department of Art and Art History is pleased to present the opening of "Sliding Scale: Gail Wight."

With this exhibit, Gail Wight adds her voice to the Imaging Environment: Maps, Models, and Metaphors conference, which brings together scholars from the humanities to consider how the environment shapes the way we study and use it.

In "Sliding Scale," Gail Wight's art playfully resists the dematerialization of objects of scientific investigation. Mice eat through a representation of their genome, butterflies struggle to escape their pins, and beetles tell their stories. Wight's art simultaneously takes on two great flaws of abstract scientific thinking: oversimplification and loss of perspective.

In Crossing, a live mouse plays with a robotic one, and the viewer is left marveling at the incredible complexity of the living being. Recursive Mutations gives a mouse the chance to redesign its own genome through its interaction with the paper it lives on.

With humor, "Sliding Scale" asks the viewer what has been lost in abstracting a mouse to its genes or to a mechanical prototype that replicates only some of its functions. As viewers zoom in and out with The Meaning of Miniscule they find that where they end up is not where they began.

Wight's art prompts viewers to see the objects of scientific research and the larger field of science in a new and different light.

The Thomas Welton Stanford Art Gallery is free and open to the public Tuesday through Friday from 10:00 a.m. until 5:00 p.m. and Saturday and Sunday from 1:00 p.m. until 5:00 p.m.  More information...

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