Science

A team of physicists at Grenoble University in France discovered that trees make different sounds when they are starved for water versus when they are simply thirsty. We hear from Dr. Alexandre Ponomarenko, the lead researcher, and hear a bit of the thirsty tree sounds.

As the inventor of the telephone, Alexander Graham Bell is credited with bringing countless voices to our ears. And now, for the first time, here he is imploring us to hear his own voice:

The sound is scratchy. You have to strain to decipher it, but the words are clear. They're from Bell's lips, recorded in 1885 but unveiled just last week by the Smithsonian.

"It lets us know what the past was really like. It fills in a gap for people," says Shari Stout, collections manager at the Smithsonian's National Museum of American History.

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RACHEL MARTIN, HOST:

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ROBERT SIEGEL, HOST:

The U.S. Navy is planning to ramp up training activities off California and Hawaii. But that has rekindled a battle over Navy sonar, which is known to harm marine mammals. From member station KQED, Lauren Sommer reports.

LAUREN SOMMER, BYLINE: We humans are visual creatures and for good reason. If someone is far away, you can usually see them before you hear them. Underwater, it's the opposite.

BRANDON SOUTHALL: The physical environment of the ocean really favors the use of sound, and the animals have evolved accordingly.

The largest current study of an AIDS vaccine, involving 2,500 people, is being stopped.

After an oversight committee took a preliminary peek at the results this past Monday, they concluded there was no way the study would show that the vaccine prevents HIV infection.

Nor would the vaccine suppress the wily virus among people who get infected despite being vaccinated.

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IRA FLATOW, HOST:

This is SCIENCE FRIDAY. I'm Ira Flatow. We're broadcasting today from the Grand Theatre at Salt Lake Community College. And, of course, just up the road from Salt Lake City is the city's namesake, the Great Salt Lake. Parts of it are 10 times saltier than the ocean. But this is no Dead Sea. It's teeming with microbes which can turn the water bubblegum pink.

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IRA FLATOW, HOST:

This is SCIENCE FRIDAY. I'm Ira Flatow.

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IRA FLATOW, HOST:

Up next, it's our Video Pick of The Week. And here with me, as always, is our managing editor and correspondent for video, Flora Litchman. Hi, Flora.

FLORA LITCHMAN, BYLINE: Hi, Ira.

FLATOW: You went on a...

(APPLAUSE)

FLATOW: You went on a local expedition for us.

LITCHMAN: I love Salt Lake City.

FLATOW: Yeah.

LITCHMAN: I just want to...

FLATOW: They love you, it sounds like. Tell us about your expedition.