10 true facts to share at dinner (with sources)
Short answer: here are ten surprising facts that are actually true, each with a one-paragraph explanation and the source it's based on.
1. Octopuses have three hearts and blue blood.
Two hearts pump blood through the gills and a third pumps it to the rest of the body. Their blood uses a copper-based protein called hemocyanin to carry oxygen, which gives it a blue color. Source: Smithsonian
2. A sugar-cube-sized piece of neutron star material would weigh about a billion tonnes on Earth.
A neutron star packs more mass than the Sun into a ball only about 20 kilometers wide. Its matter is crushed so tightly that atoms collapse into densely packed neutrons, making it one of the densest forms of matter known. Source: NASA
3. The smallest bone in the human body is the stapes in the middle ear, about 3 millimeters long.
The stapes, named after its stirrup shape, is one of three tiny bones that pass sound vibrations from the eardrum to the inner ear. It is roughly the size of a grain of rice. Source: Britannica
4. Most of Earth's volcanic activity takes place underwater.
Volcanic eruptions happen constantly along mid-ocean ridges and at undersea volcanoes, where plates spread and magma rises. Because they are hidden beneath kilometers of water, most of these eruptions go unseen. Many underwater volcanoes have never been directly observed. Source: NOAA
5. Teaching was already under way at the University of Oxford more than two centuries before the Aztec capital Tenochtitlan was founded.
Records show teaching at Oxford by 1096, and it grew quickly after 1167. Tenochtitlan was founded around 1325, and the Aztec Empire itself took shape in the 1400s. Source: University of Oxford
6. Saffron threads are the dried stigmas of a crocus flower, and each flower has only three.
The stigmas of Crocus sativus must be picked by hand, usually within a short flowering season. Because each bloom gives so little, well over 100,000 flowers are needed for a single kilogram. That is why saffron is among the most expensive spices by weight. Source: Britannica
7. The small dot over a lowercase 'i' or 'j' is called a tittle.
The word comes from Medieval Latin titulus, meaning a small mark or inscription. Scribes used dots and strokes like this to make letters easier to tell apart in handwriting. Though rarely used today, the term is still in major dictionaries. Source: Merriam-Webster
8. Bananas are very slightly radioactive because of the natural potassium they contain.
A tiny fraction of all potassium is the radioactive form potassium-40. The dose from eating a banana is extremely small and harmless, far less than the natural background radiation we get every day. Source: Health Physics Society
9. Antarctica is the largest desert in the world.
A desert is defined by how little precipitation it gets, not by heat. Much of Antarctica's interior receives less than 5 centimeters of snow-equivalent water each year, less than many hot deserts. Source: Britannica
10. Badwater Basin in Death Valley, California, is 86 meters below sea level, the lowest point in North America.
Its floor is covered in salt left by ancient lakes. Death Valley also holds some of the hottest temperatures ever recorded. Source: National Park Service
FAQ
Are these facts suitable for kids?
Yes. They are family safe and easy to explain.
Where do these facts come from?
Each one names the reference it's based on, such as NASA, Britannica or the Smithsonian.
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