Skip to main content

Frank Oppenheimer

Frank Oppenheimer

1912–1985

Frank Oppenheimer grew up in New York City. He graduated from Johns Hopkins University with a degree in physics and later earned a Ph.D. at the California Institute of Technology, where he experimented with artificially induced radiation.

In 1941, Frank began working on uranium isotope separation, and, in 1945, he joined the Manhattan Project at Los Alamos. This top-secret effort to produce an atomic bomb was directed by Frank’s brother, J. Robert Oppenheimer.

After the war, Frank became a physics professor at the University of Minnesota. But in 1949, he was forced to resign as a result of harassment by the House Un-American Activities Committee. Blackballed by McCarthy-era paranoia, Frank was unable to continue his physics research, and spent the next ten years as a cattle rancher in Pagosa Springs, Colorado.

In 1957, he was drawn back into education as a science teacher at the local high school, which had fewer than 300 students and only one science teacher for all the grades. A tireless and innovative teacher, he took students to the dump and used abandoned auto parts to teach principles of mechanics, heat, and electricity.

With improvement in the political climate, Frank was offered an appointment at the University of Colorado in 1959. There, he revamped the teaching laboratory, creating a “library of experiments” that was in many ways a prototype for the Exploratorium.

In 1965, while in Europe on a Guggenheim fellowship, Frank explored and studied European museums and became convinced of the need for science museums in the United States that could supplement the science taught in schools. When he returned home, Frank was invited to plan a new branch of the Smithsonian, but he declined, preferring instead to work on what he called his “San Francisco project”— a museum of his own.

Frank proposed to house his new museum in the vacant Palace of Fine Arts in the Marina district of San Francisco. The proposal was accepted by the city, and in 1969, with no publicity or fanfare, the doors opened to Frank’s Exploratorium. Frank nurtured and shaped the growing museum until 1985, when he died from lung cancer.

The qualities that made Frank so special are the same qualities that make the Exploratorium special: an insistence on excellence, a knack for finding new ways of looking at things, a lack of pretentiousness, and a respect for invention and play.

Related Snacks

What’s going on?

Ordinarily, the world around you is lit by light of many different colors. When this many-colored light bounces off of things, some colors get absorbed, while others get reflected. It’s the light reflecting off objects that give them their apparent color. For example, a sweater looks red because it reflects red light into your eyes.

In this room, there is no red light to bounce off of things and make them look red. There’s no blue light or green light either. With only a single color to absorb or reflect, objects look to be more or less the same color.

What’s going on?

There’s really no end to the discoveries possible at this exhibit. But there’s one phenomenon that most people find delightfully baffling: Hold up a screen with holes of various shapes punched in it—a circle, a square, a star—and the patterns of light and shadow made by each aren’t at all what you’d expect. You don’t see a circle, a square, or a star—but instead an upside-down image of the letter F—which happens to be the shape of the light source.

Light passing through small holes or gaps behaves like light in a pinhole camera—light rays from the source cross and invert as they make their way through the hole. Provided the light source is far enough away, the exact shape of the hole doesn’t matter.

Similar optics are in play when you see dappled circles of light beneath a leafy tree. Those perfect circles of light don’t come from perfectly circular gaps between the leaves—they are images of the circular Sun.

During an eclipse, it’s easy to see that light passing through a small hole takes the shape not of the hole, but of the light source. (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

Related Snacks

What’s going on?

Ordinarily, the world around you is lit by light of many different colors. When this many-colored light bounces off of things, some colors get absorbed, while others get reflected. It’s the light reflecting off objects that give them their apparent color. For example, a sweater looks red because it reflects red light into your eyes.

In this room, there is no red light to bounce off of things and make them look red. There’s no blue light or green light either. With only a single color to absorb or reflect, objects look to be more or less the same color.

What’s going on?

There’s really no end to the discoveries possible at this exhibit. But there’s one phenomenon that most people find delightfully baffling: Hold up a screen with holes of various shapes punched in it—a circle, a square, a star—and the patterns of light and shadow made by each aren’t at all what you’d expect. You don’t see a circle, a square, or a star—but instead an upside-down image of the letter F—which happens to be the shape of the light source.

Light passing through small holes or gaps behaves like light in a pinhole camera—light rays from the source cross and invert as they make their way through the hole. Provided the light source is far enough away, the exact shape of the hole doesn’t matter.

Similar optics are in play when you see dappled circles of light beneath a leafy tree. Those perfect circles of light don’t come from perfectly circular gaps between the leaves—they are images of the circular Sun.

During an eclipse, it’s easy to see that light passing through a small hole takes the shape not of the hole, but of the light source. (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