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Charles Sowers: Staff Artists

Charles Sowers
Exhibit Developer

An artist and exhibit developer, Charles has been making thought-provoking, beautiful, and sometimes whimsical experiences for Exploratorium visitors since 1998. His work presents actual physical phenomena—often of striking visual beauty—that draw people into a careful noticing and interaction. He seeks to provoke a sense of delight and wonder and reward extended observation. Frequently this involves developing an apparatus to recreate or highlight some natural phenomenon. Charles frequently collaborates with scientists to recreate lab experiments. Through these collaborations, he has discovered a strong correlation between his process and that of the scientific experimentalist. Both build apparatuses—scientists to probe the limits of their collective understanding and Charles to probe the boundaries of beauty, delight, and wonder.

What’s going on?

This jaw-dropping spherical mirror was loaned to us by friends at the Smithsonian Institution.

Designed to be part of a flight simulator, a small flaw (you can look, but you won’t find it) made it unusable for its intended purpose. And boy, are we glad, because this is probably our single most popular exhibit. Is it narcissism—or love of optics?

This mirror’s concave spherical shape focuses incoming light to a point—called the focal point—about 1.5 meters (5 feet) from its surface. Depending on where you stand relative to this focal point, you can give yourself a high five, watch a friend’s head shrink and explode, or enjoy a super-sharp view of distant objects. Walk slowly toward the mirror from beyond the focal point and you’ll see your own head seem to explode just as you pass through it.

As astounding as this mirror appears in person, the optical tricks it plays are not fundamentally different from those you can see in other concave spherical reflectors, such as a magnifying makeup mirror or even just the hollow side of a metal spoon. The main difference is its spectacular size—and a near-perfect smoothness that makes for exceptional clarity.

Can you come up with any new tricks? Let us know.

Diagram showing the concave nature of the Giant Mirror exhibit. Like all concave mirrors, the Giant Mirror focuses incoming light (and sound) to a single point, called the focal point. (click image to enlarge)

Related Snacks

What’s going on?

The parabolic shape of this array of mirrors focuses incoming light rays together, causing them to converge to a single point (called the focal point) and then spread apart again. When you put your own eyeball at just the right place—roughly twice the focal length—you see your own eye reflected back at you from every mirror in the array.

Berenice Abbott photo of parabolic mirrors. This exhibit was inspired by a photo from a classic physics textbook. The Parabolic Mirror Has a Thousand Eyes was shot by the famous scientific photographer Berenice Abbott. (click image to enlarge)

What’s going on?

Electricity flows between the two submerged wires of this exhibit, causing chemical changes in the liquid that you see as a change in color.

The liquid in this tank is mostly water with a little salt and some special dyes. The dyes turn yellow where there are positive hydrogen ions and bluish-purple where there are negative hydroxide ions.

The dyes are pH indicators—they show whether the liquid is acidic or alkaline. By definition, acidic things like lemon juice are substances that contain an overabundance of positive hydrogen ions. Alkaline substances contain an overabundance of negative hydroxide ions. So the yellow in the tank is acidic, while the bluish-purple is alkaline.

Related Exhibits

What’s going on?

This jaw-dropping spherical mirror was loaned to us by friends at the Smithsonian Institution.

Designed to be part of a flight simulator, a small flaw (you can look, but you won’t find it) made it unusable for its intended purpose. And boy, are we glad, because this is probably our single most popular exhibit. Is it narcissism—or love of optics?

This mirror’s concave spherical shape focuses incoming light to a point—called the focal point—about 1.5 meters (5 feet) from its surface. Depending on where you stand relative to this focal point, you can give yourself a high five, watch a friend’s head shrink and explode, or enjoy a super-sharp view of distant objects. Walk slowly toward the mirror from beyond the focal point and you’ll see your own head seem to explode just as you pass through it.

As astounding as this mirror appears in person, the optical tricks it plays are not fundamentally different from those you can see in other concave spherical reflectors, such as a magnifying makeup mirror or even just the hollow side of a metal spoon. The main difference is its spectacular size—and a near-perfect smoothness that makes for exceptional clarity.

Can you come up with any new tricks? Let us know.

Diagram showing the concave nature of the Giant Mirror exhibit. Like all concave mirrors, the Giant Mirror focuses incoming light (and sound) to a single point, called the focal point. (click image to enlarge)

Related Snacks

What’s going on?

The parabolic shape of this array of mirrors focuses incoming light rays together, causing them to converge to a single point (called the focal point) and then spread apart again. When you put your own eyeball at just the right place—roughly twice the focal length—you see your own eye reflected back at you from every mirror in the array.

Berenice Abbott photo of parabolic mirrors. This exhibit was inspired by a photo from a classic physics textbook. The Parabolic Mirror Has a Thousand Eyes was shot by the famous scientific photographer Berenice Abbott. (click image to enlarge)

What’s going on?

Electricity flows between the two submerged wires of this exhibit, causing chemical changes in the liquid that you see as a change in color.

The liquid in this tank is mostly water with a little salt and some special dyes. The dyes turn yellow where there are positive hydrogen ions and bluish-purple where there are negative hydroxide ions.

The dyes are pH indicators—they show whether the liquid is acidic or alkaline. By definition, acidic things like lemon juice are substances that contain an overabundance of positive hydrogen ions. Alkaline substances contain an overabundance of negative hydroxide ions. So the yellow in the tank is acidic, while the bluish-purple is alkaline.

Related Exhibits