Confederate paper money was a promise to exchange the bill for gold or silver, but only after the Confederacy won the war.
People have painted on cave walls and written on clay and wax tablets, papyrus and paper made from wood. Could screens replace paper someday?
Only one president has done so – Franklin Delano Roosevelt – but others considered it, and even tried.
The U.S. is broken up into 50 states, plus territories like Puerto Rico and Guam, and a federal district, Washington, D.C. Most other countries have smaller parts too.
Our biggest evolutionary advantages are an ability to walk on two legs and our big brains.
Even if every human being on Earth went for a dip in the ocean at the same time, they'd be just a drop in the bucket compared to the size of the planet's seas.
Where we would be without our brains? But think about it. How do they work?
Going to the bathroom is much more complicated in space without any gravity. To solve this problem of tricky orbital potty breaks, NASA builds special toilets that work without gravity.
Research shows multiple social and cognitive benefits of playing video games.
Not all flowers smell good, to people at least, but their scents are a way to attract pollinators.
Arctic foxes have a few special talents that help them sneak up on unseen prey and pounce.
Dogs' barks say a lot about how they're feeling.
If you are a sci-fi junkie you've probably wondered what would happen if you were unlucky enough to fall into a black hole. How well you'd fare all depends on the type of black hole.
When planes fly from east to west, they are flying against a river of air called a jet stream. These air currents can make your flight longer or shorter, depending on which way you are going.
Grammar isn't a way to bully people for making mistakes, says a longtime English instructor. It is a way to understand how our language operates, in all its many written and spoken varieties.
The mystery of how the brain creates consciousness still puzzles scientists, but the mechanics of waking up are starting to be understood.
There are 15 different kinds of electrical outlets around the world. One standard would be more convenient, but no one wants to change theirs.
Mermaids are not real, but are meaningful to people around the world.
How do tigers – a top predator – successfully hunt their prey when they have bright orange fur? The secret's in their stripes!
Geese honk loudly and point their bills toward the sky when they're ready to start the migration. Here's how they know it's time, how they navigate and how they conserve energy on the grueling trip.