Air Date: Week of March 7, 2003

Living on Earth’s Cynthia Graber reports on bubble experiments in space.

Transcript

ROSS: Coming up, how pollution levels in one San Diego neighborhood shocked regulators into action. First, this note on Emerging Science, from Cynthia Graber.

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GRABER: American astronaut, Don Pettit, has been living on the International Space Station for the past three months, and he says he enjoys Saturday mornings when he has some free time. During these hours, Pettit likes to conduct imaginative scientific experiments. Recently, he decided to see how bubbles behaved in zero gravity. So he prepared a solution of soapy water and made himself a bubble wand out of wire. But first, he decided to try the experiment with plain old water.

To his surprise, the water formed a film on his wire loop that lasted for hours. He could blow on it and even paint on it with drops of food coloring. And the water film could hold securely onto a much larger loop than it could here on earth. In general, water forms a film because of what's known as surface tension. Fat arises because water molecules are electrically charged. The positive side of one molecule is drawn to the negative side of another. So water molecules actually cling to one another. But on earth, gravity overcomes this surface tension and pull film apart. In the gravity-free environment of the space station, Pettit found some of these water films lasted up to 12 hours.

There are serious scientific applications to this work. This type of research helps scientists understand more about the physics of fluids here on earth. That's this week's note on Emerging Science, I'm Cynthia Graber.

ROSS: And you're listening to Living On Earth.

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ROSS: Welcome back to Living On Earth. I'm Pippin Ross.

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ROSS: Out on the safaris, writes Isak Dinesen in “Out of Africa,” I had seen a herd of buffalo, 129 of them, come out of the morning mist under a copper sky, one by one, as if the dark and massive iron-like animals were not approaching, but were being created before my eyes and sent out as they were finished. I had, time after time, watched the progression across the plain of the giraffe, in their queer vegetative gracefulness, as if it were not a herd of animals, but a family of rare, long-stemmed, speckled, gigantic flowers slowly advancing. I had followed two rhinos on their morning promenade when they were sniffing and snorting in the air of the dawn, and looked like two very big angular stones rollicking in the long valley and enjoying life together.

Thanks to Heritage Africa, you too can experience the wild as Dinesen did. Living On Earth is giving away a 15-day trip for two on the Ultimate African Safari, with visits to several of Africa's most spectacular game preserves, such as Kruger in the Serengeti. Please go to our website, loe.org for more details on how to win this 15-day trip to see some of Africa's most spectacular sites. That's loe.org.

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