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Helium Conservation

The element helium makes up one quarter of the mass of the visible universe . . . . . . but only about one millionth of one percent of Earth’s atmosphere and crust. That’s because helium is so light that — once released into the atmosphere — it escapes into outer space. Also, helium’s an inert gas — it doesn’t bond with any other elements …

Satellites and Disease

On the use of satellites orbiting Earth in helping to stop the spread of disease. For example, malaria is carried by a certain kind of mosquito. Nearly two million people, mostly children, die of this disease every year. And about 90% of cases and deaths occur in sub-Saharan Africa. Epidemiologists are now using satellite data in this region to identify the habitats of the mosquitoes …

Cool Sounds

Most modern refrigerators use chemicals called Hydro-Chloroflurocarbons — or HCFCs. If these chemicals leak into the air, they act as greenhouse gases. They’re thousands of times better at holding in heat than carbon dioxide. That’s why scientists at Penn State University are developing more environmentally friendly refrigerators. Instead of using HCFC’s, the new fridges use helium and sound waves. Here’s acoustics researcher Matt Poese: Matt …

What in helium makes your voice turn high?

Sound gets started when a vibrating source — imagine a guitar string — pushes air particles out of the way. Those air particles bump neighboring particles. The particles move back and forth as the sound source vibrates. The faster the movement of the air particles, the higher-pitched the sound. Helium gas is lighter than the air around us. So sound waves moving through helium bounce …

Saturn’s Rings

In Ocboer of 2002, the Cassini spacecraft took its first picture of the planet Saturn.┬áThe picture shows Saturn’s trademark — its glorious rings. Philip Nicholson: A lot of us … who work on the rings became fascinated by them partly because they’re just so beautiful and so elegant. And that hasn’t gone away. That’s Phillip Nicholson, on the Cassini science team. He’s eagerly awaiting the …

If space is expanding, why do galaxies collide?

Hi, my name is Lyn Neale, and I’ve always wondered if the Big Bang theory is correct, how can there be collisions of galaxies in space? Lyn, the Big Bang theory proposes that billions of years ago, the universe exploded from a tiny point. The first rapid expansion, which scientists call inflation, occurred in a fraction of a second. After inflation, the universe expanded more …