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1:02:13
In this zany competition teachers will have ten minutes to create a science activity from a special St. Patrick's Day secret ingredient-things that are green!

1:17:34
How do opera singers sing loud enough to be heard over an orchestra? Can an opera singer's voice really break a wine glass? What's the difference between a baritone and a soprano? Discover the answers to these questions—and more!—in this presentation for families. Join physicist and composer Dr. Brian Holmes and San Francisco Opera Center Director Sheri Greenawald to explore how the art and science of singing combine in opera.

01:04:45
Watch as Exploratorium staff and local teachers compete for the title of Iron Science Teacher. Each contestant has ten minutes to make a science lesson out of a secret ingredient. Today's secret ingredient-potatoes!

00:03:07
If you’ve ever gone to hear an orchestra play, you know that the performance begins only after a session of tuning. An oft-repeated story tells of a visiting foreigner attending a concert in Paris. Afterwards, when asked which part of the performance he liked best, he replied, “The beginning, just before the man with the stick came in.” Tuning means adjusting the pitch of an instrument. The pitch of a sound depends on its frequency, the number of vibrations per second that produce the sound. For example, plucking a cello string might cause it to vibrate back and forth 200 times each second. You hear that sound as a low pitch of 200 cycles per second, or 200 hertz. An orchestra tunes itself to a very particular frequency, usually 440 hertz, a note known as A 440. The note is played by the oboist, and the rest of the orchestra tunes their instruments to match it. The oboe leads the tuning because of all the instruments, it is least affected by humidity or other weather conditions.

00:02:29
Music is more than meets the ears directly. Just as no sound exists in a vacuum, every space sculpts the sound within it. Like a site-specific equalizer, reflections, absorption, and resonances combine to give each venue a unique acoustic stamp. A subway tunnel is “live” space, rich with reverberations that trap and reflect sound in a well of hard tile. True to their name, “dead” spaces do nothing: The only sound heard is what travels directly from instrument to ear. An open field is the ultimate dead space. As you follow this wandering riff, listen to the changes wrought by environment. Distance is also a factor here—the sound you hear is recorded from the camera’s vantage. Which spaces sound live? Which sound dead? Do the acoustic changes affect the feeling of the music? Saxophonist Michael Pearce plays with the Highwater Blues Band in the San Francisco Bay Area.

1:00:11
Watch as the best teachers on the planet battle it out for the title of Iron Science Teacher. In this zany competition teachers will have ten minutes to create a science activity. This week's "secret" ingredient - Valentine gifts!

00:45:44
NASA's Mars Exploration Rovers, Spirit and Opportunity, have long outlived their life expectancy of three months. Join us as we sum up the rover data and explain how this information changes our view of Mars.

1:01:08
Watch as the best teachers on the planet battle it out for the title of Iron Science Teacher. In this zany competition teachers will have ten minutes to create a science activity. This week’s “secret” ingredient- carbohydrates!

00:29:21
We update on the week's exciting events on Mars and talk about what NASA has planned for future missions to the Red Planet.

00:23:48
How do JPL scientists and engineers talk to the MERs and how do we receive those amazing pictures in return? Find out how, and get the latest updates in this webcast.