All Facts
Every fact here links to the source it was checked against.
Decaf Coffee Still Contains Caffeine
Decaffeinated coffee is not caffeine-free: an 8-fluid-ounce cup of decaf coffee typically has 2 to 15 milligrams of caffeine.
Everyone Dreams for About Two Hours a Night
Everyone dreams, spending about two hours each night dreaming, although most dreams are not remembered.
People Spend About a Third of Their Time Asleep
People spend about one-third of their time sleeping.
Thunder Can Be Heard Only About 10 Miles Away
Thunder is the sound caused by a nearby flash of lightning, and it can be heard for a distance of only about 10 miles from the strike.
The First Flight Faster Than Sound Was on October 14, 1947
On October 14, 1947, the Bell X-1, piloted by Chuck Yeager, became the first airplane to fly faster than the speed of sound.
Lindbergh's Flight From New York to Paris Took 33 and a Half Hours
Charles Lindbergh's solo flight from New York to Paris in May 1927 took 33 hours and 30 minutes and covered 3,610 miles.
Your Heart Is About the Size of Your Fist
The human heart is an organ about the size of your fist that pumps blood through your body.
The Human Brain Weighs About Three Pounds
The human brain is a three-pound organ, described by the US National Institutes of Health as the most complex part of the human body.
Skin Is the Biggest Organ of the Human Body
Skin is the biggest organ of the human body, and it is organized into three main layers.
Mammoth Cave Is the Longest Known Cave System in the World
Mammoth Cave in Kentucky is the world's longest known cave system.
The Hottest Air Temperature Ever Recorded Was in Death Valley
The world record highest air temperature, 134°F (57°C), was recorded at Furnace Creek in Death Valley on July 10, 1913.
The Grand Canyon Is 278 River Miles Long and a Mile Deep
The Grand Canyon is 278 river miles long, up to 18 miles wide from rim to rim, and one mile deep on average.
The Longest Mountain Range on Earth Is Mostly Under the Ocean
The longest mountain range on Earth is the mid-ocean ridge, which spans 40,389 miles around the globe, with about 90 percent of it under the ocean.
Tsunami Waves Can Travel as Fast as a Jet Plane
Over deep water, tsunami waves may travel as fast as jet planes, slowing down only when they reach shallow water.
Seawater Is About 3.5 Percent Salt
About 3.5 percent of the weight of seawater comes from dissolved salts, which come mainly from rocks on land and openings in the seafloor.
About Half of Earth's Oxygen Comes From the Ocean
Scientists estimate that roughly half of the oxygen production on Earth comes from the ocean, mostly from tiny photosynthetic plankton.
Corals Are Animals, Not Plants
Corals are animals, not plants: most coral structures are made up of hundreds to thousands of tiny creatures called polyps.
Starfish Are Not Fish and Have No Blood
Sea stars, commonly called starfish, are not fish: they have no gills, scales or fins, and they use sea water instead of blood to pump nutrients through their bodies.
Male Seahorses Get Pregnant and Give Birth
Seahorses and their close relatives, sea dragons, are the only species in which the male gets pregnant and gives birth.
The Killer Whale Is the Largest Dolphin
The killer whale, or orca, is the largest member of the dolphin family.