Environmental Science

Solar energy is clean and plentiful. There's one big problem, though: The sun doesn't shine all the time. Is there a way to keep solar plants powered up through the night?

By Julia Layton

The oceans' levels change daily across the globe. We know them as tidal changes. But what causes this constant shift in sea level and why is it more dramatic is some places than others?

By Mark Mancini

Alternative energy usually means something is mined, refined, collected or grown. But gravity-powered floor lamps rely only on a force of nature -- and the strength of a human being.

By Julia Layton

Photovoltaic solar panels are like windows -- they build up a coating of grime that requires a good cleaning from time to time. What's the alternative to climbing the roof with a squeegee and bucket of suds?

By Maria Trimarchi

Gasification could represent a second chance for coal. Will this old technology, which can run on coal or biomass, get a new life as one of the most important energy alternatives of the future?

By William Harris

How much energy does your TV use when it's plugged in all night? How much power is your stereo system draining from the socket monthly? The Kill A Watt and other energy monitors help you find out.

By Julia Layton

Cellulosic ethanol can be made from any old stem, leaf or tree trunk. Farm wastes, grass clippings and recycled newspaper will work, too. So when can we expect this alternative fuel to arrive at gas stations?

By Susan L. Nasr

At best, fossilization is a long and tricky process that mineralizes an occasional Tyrannosaurus rex or other extraordinary find. How has that affected our chances at charting a model of life itself?

By Robert Lamb

It's not so much about time as it is about money. What dictates how long an archeological team is permitted to dig at a particular site?

By Charles W. Bryant

Each country and each region within each country has its own laws regarding the right to cultural property. So, how do you know which artifacts belong to the government and which are "finders keepers"?

By Charles W. Bryant

In "The Raiders of the Lost Ark," Indiana Jones competes with grave-robbing Nazis for the lost Ark of the Covenant. But what defined Dr. Jones as legit and the Nazis as grave robbers?

By Charles W. Bryant

Men have been hunting and killing whales for centuries. Early whalers hunted for survival, but their motivation may have changed once there was money to be made. Whaling for profit has been banned since 1986, but whaling for scientific research is still allowed in certain areas, causing much debate.

By Alison Kim Perry

Without its keystone, a Roman aqueduct collapses. Does the same travesty befall an ecosystem when a keystone species goes missing from the ecological equation?

By William Harris

Recycling is a pretty simple concept: take something that isn't useful anymore and make it into something new. Learn about the process and the good and bad of recycling.

By Ed Grabianowski

While actual footprints measure size, weight and speed, carbon footprints measure how much carbon dioxide (CO2) we produce in our daily lives. Do you know how big your carbon footprint is?

By Sarah Dowdey

Eco-conscious people purchase carbon offsets to help reduce worldwide greenhouse gas emissions. But do offsets actually help, and what does Pink Floyd have to do with them?

By Sarah Dowdey

In "Back to the Future," Doc Brown throws garbage into Mr. Fusion, powering his time machine. We might be closer than you think to generating electricity for our homes using trash.

By Jonathan Strickland

The Bulletin of Atomic Scientists moved the Doomsday Clock to 90 seconds before midnight, the closest it's ever been to global catastrophe. What does this mean for humanity?

By Julia Layton

A map is a type of language, a graphic way of representing information, whether it's to show population density or tell you how to get from Point A to Point B. Here's how they're made.

By Tracy V. Wilson & Alia Hoyt

Diamond engagement rings. Diamond anniversary bands. Diamond earrings and necklaces. And now, the right-hand diamond ring! The four Cs -- cut, clarity, carat and color. Find out what the fuss is all about.

By Kevin Bonsor

Rip currents are the number-one concern for beach lifeguards: About 80 percent of all beach rescues are related to rip currents. Learn what they are and what you should do if you get caught in one.

By Tom Harris

Countless movies and television shows depict quicksand as some kind of living creature that sucks its victims down into a bottomless pit, never to be heard from again. Well, you can't believe everything Hollywood tells you.

By Kevin Bonsor

Manhole covers have been blasting out of the ground in New York City. Find out what causes these strange explosions and how powerful they really are.

By Kevin Bonsor

The basic idea isn't new, but the process of modern hydropower conversion is high-tech. Today's hydropower plants are some of the coolest machines ever constructed. Find out how rushing water generates power.

By Kevin Bonsor

Few things have done as much harm to humanity as fire, and few things have done as much good. Find out where fire comes from and see why it behaves the way it does. The answers might surprise you!

By Tom Harris