curious questions
why does popcorn pop
"Inside each kernel of popcorn is a tiny droplet of water surrounded by a hard shell called a hull. As the popcorn is heated, the water turns into steam, which builds pressure inside the kernel. When the hull can no longer contain the pressure —POP! — the kernel explodes, and a fluffy new piece of popcorn is born.
how much land is on earth? "The total land surface area of Earth is about ___________ square ___________ , of which about _______% is desert and about ______% is mountainous. Subtracting this ___________ 57% (32,665,981 mi2) from the total land area leaves ___________ square miles or ___________ billion acres of habitable land."
"The total land surface area of Earth is about 57,308,738 square miles, of which about 33% is desert and about 24% is mountainous. Subtracting this uninhabitable 57% (32,665,981 mi2) from the total land area leaves 24,642,757 square miles or 15.77 billion acres of habitable land."
how old is the earth
4.543 billion years
The current (2018) world population is
7.6 billion
why do birds flock in v form
A new study of ibises finds that these big-winged birds carefully position their wingtips and sync their flapping, presumably to catch the preceding bird's updraft—and save energy during flight. There are two reasons birds might fly in a V formation: It may make flight easier, or they're simply following the leader
how does a plane stay in the air
A plane's engines are designed to move it forward at high speed. That makes air flow rapidly over the wings, which throw the air down toward the ground, generating an upward force called lift that overcomes the plane's weight and holds it in the sky. ... The wings force the air downward and that pushes the plane upward.
what makes a rainbow appear
A rainbow is a meteorological phenomenon that is caused by reflection, refraction and dispersion of light in water droplets resulting in a spectrum of light appearing in the sky. It takes the form of a multicoloured circular arc. Rainbows caused by sunlight always appear in the section of sky directly opposite the sun.
what makes a skunk smell?
A skunk's spray is made up of oily chemicals called thiols. Thiols are sulphur compounds that can cause headaches and burning or stinging in the eyes. The worst part, though, is the smell. a sunk can spray about 10 feet.
what keep my bones together
A tendon is a fibrous connective tissue which attaches muscle to bone. Tendons may also attach muscles to structures such as the eyeball. ... A ligament is a fibrous connective tissue which attaches bone to bone, and usually serves to hold structures together and keep them stable
why is a four leaf clover lucky
About 1 specimen in 10,000 of Trifolium repens (aka white clover) has four leaves instead of the usual three. "Saint Patrick was said to use the shamrock, the three-leaf clover, to teach about the Holy Trinity," Prescott said. "Whereas the four-leaf version is supposed to stand for faith, hope, love and luck.
why is it considered unlucky to open an umbrella inside
According to superstition, bad luck will "rain" on you if you open an umbrella indoors. One explanation comes from the days when umbrellas were used as protection from the sun; opening one inside was an insult to the sun god
when was the first postage stamp used
Although a number of people laid claim to the concept of the postage stamp, it is well documented that stamps were first introduced in the United Kingdom of Great Britain and Ireland on 1 May 1840 as a part of postal reforms promoted by Sir Rowland Hill.
what causes an eclipse of the sun
An eclipse of the Sun (or solar eclipse) can only occur at New Moon when the Moon passes between Earth and Sun. If the Moon's shadow happens to fall upon Earth's surface at that time, we see some portion of the Sun's disk covered or 'eclipsed' by the Moon
who invented ice cream
An ice-cream-like food was first eaten in China in 618-97AD. King Tang of Shang, had 94 ice men who helped to make a dish of buffalo milk, flour and camphor. A kind of ice-cream was invented in China about 200 BC when a milk and rice mixture was frozen by packing it into snow.
how a light bulb works
An incandescent bulb typically consists of a glass enclosure containing a tungsten filament. An electric current passes through the filament, heating it to a temperature that produces light.
who invented pizza
An often recounted story holds that on 11 June 1889, to honour the Queen consort of Italy, Margherita of Savoy, the Neapolitan pizzamaker Raffaele Esposito created the "Pizza Margherita", a pizza garnished with tomatoes, mozzarella, and basil, to represent the national colours of Italy as on the Italian flag.
when and where were the first olympics held
Athens, Greece on April 6, 1896 - April 15, 1896
what is glass made of
Believe it or not, glass is made from liquid sand. You can make glass by heating ordinary sand (which is mostly made of silicon dioxide) until it melts and turns into a liquid. You won't find that happening on your local beach: sand melts at the incredibly high temperature of 1700°C (3090°F)
what's the difference fruits and vegetables
Botanically speaking, a fruit is a seed-bearing structure that develops from the ovary of a flowering plant, whereas vegetables are all other plant parts, such as roots, leaves and stems.
why do leaves change color
Chlorophyll Breaks Down. But in the fall, because of changes in the length of daylight and changes in temperature, the leaves stop their food-making process. The chlorophyll breaks down, the green color disappears, and the yellow to orange colors become visible and give the leaves part of their fall splendor.
where does chocolate come from
Chocolate is made from cocoa beans, the dried and fermented seeds of the cacao tree (Theobroma cacao), a small, 4-8 m tall (15-26 ft tall) evergreen tree native to the deep tropical region of the Americas.
how do clouds form
Clouds form when the invisible water vapour in the air condenses into visible water droplets or ice crystals. There is water around us all the time in the form of tiny gas particles, also known as water vapour. There are also tiny particles floating around in the air - such as salt and dust - these are called aerosols.
Who had the White House built?
Construction began when the first cornerstone was laid in October of 1792. Although President Washington oversaw the construction of the house, he never lived in it. It was not until 1800, when the White House was nearly completed, that its first residents, President John Adams and his wife Abigail, moved in. President John Adams and his wife, Abigail, moved into the unfinished house in 1800. During the War of 1812, the British set fire to the President's House in 1814.
how long does it take for food to pass through your body
Digestion time varies between individuals and between men and women. After you eat, it takes about six to eight hours for food to pass through your stomach and small intestine. Food then enters your large intestine (colon) for further digestion, absorption of water and, finally, elimination of undigested food.
why does the moon change shape in the sky
During the lunar month, the Moon goes through all its phases. You can see the phases drawn in the image below. Just like the Earth, half of the Moon is lit by the Sun while the other half is in darkness. ... We only see the Moon because sunlight reflects back to us from its surface.
what does ESP stand for
ESP stand for extra sensory perception
how much water is there in a watermelon
Each bite of watermelon contains about 92 percent water and 6 percent sugar. Since it consists mostly of water, its name makes perfect sense! Despite being mostly water with a bit of sugar, watermelon is considered a very healthy snack. Its high water content helps keep you hydrated.
why am i dizzy when i spin around
Each hair is connected to a nerve cell that carries signals to the brain when the head moves. Spinning make you dizzy because the fluid in your ears is spinning round and round so when you stop spinning you are dizzy because the fluid is spinning.
what causes earthquakes
Earthquake environmental effects are the effects caused by an earthquake on the natural environment, including surface faulting, [[tectonic tsunamis, soil liquefactions, ground resonance, landslides and ground failure, either directly linked to the earthquake source or provoked by the ground shaking.
when was the first car invented
Exactly who invented the automobile is a matter of opinion. If we had to give credit to one inventor, it would probably be Karl Benz from Germany. Many suggest that he created the first true automobile in 1885/1886.
how long have escalators been around
Finally, in 1892, Jesse W. Reno patented the "Endless Conveyor or Elevator." He also produced the first working escalator — he called it an "inclined elevator" — and installed it along the Old Iron Pier at Coney Island in New York City in 1896.
why do flowers have color
Flowers that are bright in color are meant to attract birds, bees and other insects in order to help the plants reproduce. Bright colors or dull colors are fixed in the genetics of a flower. ... When they land on another flower some of that pollen will spread and voila! Pollination occurs.May 22, 2015
what's the difference between a spider and an insect?
For insects, they have three pairs of legs or six legs. On the other hand, spiders have four pairs or eight legs. Spiders and insects also have a difference when it comes to their major body parts. Spiders only have two main body parts while insects have three main body parts.insects have antennae; spiders dont.
why does hot water clean better than cold water
Hot water, by definition, has faster moving molecules than cold water. (The molecular speed translates into heat.) All other things being equal, faster moving molecules do a better job of cleaning than slower moving molecules (in "displacing" the dirt and transporting it away using water.
how does airship work
How Blimps Work. Airships are called lighter-than-air (LTA) craft because to generate lift, they use gases that are lighter than air. The most common gas in use today is helium, which has a lifting capacity of 0.064 lb/ft3 (1.02 kg/m3).
why are some clouds white gray or black
However, rain clouds are gray instead of white because of their thickness, or height. That is, a cloud gets thicker and denser as it gathers more water droplets and ice crystals — the thicker it gets, the more light it scatters, resulting in less light penetrating all the way through it.
how big was the biggest iceberg ever
Iceberg B-15 was the world's largest recorded iceberg. It measured around 295 kilometres (183 mi) long and 37 kilometres (23 mi) wide, with a surface area of 11,000 square kilometres (4,200 sq mi)—larger than the whole island of Jamaica.
why do we sneeze
If you just sneezed, something was probably irritating or tickling the inside of your nose. Sneezing, also called sternutation, is your body's way of removing an irritation from your nose. When the inside of your nose gets a tickle, a message is sent to a special part of your brain called the sneeze center.
why do i see myself in the mirror
In the daytime, light reflects off your body in all directions. That's why you can see yourself and other people can see you. ... The light will reflect off the mirror in a more orderly way than it reflects off your clothes. We call that specular reflection—it's the opposite to diffuse reflection
how does ice in a skating rink keep from melting
Its the same system just a lot larger and more expensive to run. They can melt, but refrigerated rinks... the ones that seem not to melt are like if you took a freezer and imbedded it into concrete. It keeps the area cool enough to support freezing of water. The rink has to be kept cold so the ice stays frozen.
when were roller skates invented
John Joseph Merlin invented roller skates in 1759 but he didn't know to stop and crashed into a full length mirror breaking his violin.
what makes a volcano erupt
Magma rises through cracks or weaknesses in the Earth's crust. When this pressure is released, eg as a result of plate movement, magma explodes to the surface causing a volcanic eruption. The lava from the eruption cools to form new crust. Over time, after several eruptions, the rock builds up and a volcano forms.
how does a microwave work
Microwave ovens are so quick and efficient because they channel heat energy directly to the molecules (tiny particles) inside food. Microwaves heat food like the sun heats your face—by radiation. A microwave is much like the electromagnetic waves that zap through the air from TV and radio transmitters.May 3, 2018
why does the sky change color from red at dawn to blue during the day
Molecules and small particles in the atmosphere change the direction of light rays, causing them to scatter and resulting in colorful sunsets. ... "Because the sun is low on the horizon, sunlight passes through more air at sunset and sunrise than during the day, when the sun is higher in the sky.Molecules and small particles in the atmosphere change the direction of light rays, causing them to scatter and resulting in colorful sunsets. ... "Because the sun is low on the horizon, sunlight passes through more air at sunset and sunrise than during the day, when the sun is higher in the sky.
why do tides rise and fall
Ocean levels fluctuate daily as the sun, moon and earth interact. As the moon travels around the earth and as they, together, travel around the sun, the combined gravitational forces cause the world's oceans to rise and fall. Since the earth is rotating while this is happening, two tides occur each day.
who built the taj mahal and why
Often described as one of the wonders of the world, the stunning 17th Century white marble Taj Mahal was built by Mughal emperor Shah Jahan as a mausoleum for his beloved wife Mumtaz Mahal, who died in childbirth.
who was the first person in space
On 12 April 1961, Russian cosmonaut Yuri Gagarin became the first human to travel into space when he launched into orbit on the Vostok 3KA-3 spacecraft (Vostok 1)
who was the first person to set foot on the Moon
On July 20, 1969, Neil Armstrong became the first human to step on the moon. He and Aldrin walked around for three hours.
how does quicksand work
Quicksand is a colloid hydrogel consisting of fine granular material (such as sand, silt or clay), and water. Quicksand forms in saturated loose sand when the sand is suddenly agitated. When water in the sand cannot escape, it creates a liquefied soil that loses strength and cannot support weight.
who keeps the world longest diary
Robert Shields, formerly (and perhaps currently) of Dayton, Washington, is a hypergraphiac who has authored the world's longest diary. For the last 20 years, Shields has kept a record of everything that has ever happened to him.
who invented comic books invented
Rudolphe Töpffer
why is the sea salty
Salt in the ocean comes from rocks on land. The rain that falls on the land contains some dissolved carbon dioxide from the surrounding air. This causes the rainwater to be slightly acidic due to carbonic acid (which forms from carbon dioxide and water). ... Sodium and Chloride are 'salty.'
how can scientists tell how old a fossil is
Scientists combine several well-tested techniques to find out the ages of fossils. The most important are Relative Dating, in which fossils and layers of rock are placed in order from older to younger, and Radiometric Dating, which allows the actual ages of certain types of rock to be calculated. Relative Dating.
why do people snore
Snoring happens when you can't move air freely through your nose and throat during sleep. This makes the surrounding tissues vibrate, which produces the familiar snoring sound. People who snore often have too much throat and nasal tissue or "floppy" tissue that is more prone to vibrate.
what make snow
Snow forms when tiny ice crystals in clouds stick together to become snowflakes. If enough crystals stick together, they'll become heavy enough to fall to the ground. ... Snow is formed when temperatures are low and there is moisture in the atmosphere in the form of tiny ice crystals.
how does the holes get in swiss cheese
That bacteria, more specifically P. shermani, releases carbon dioxide when it consumes the lactic acid and forms bubbles. The bubbles don't just disappear, they form little air pockets, resulting in the holes of the Swiss cheese.
where is the largest library in the world
The Library of Congress, of course! Built in 1800 in Washington, D.C., it's the largest library in the world in both shelf space and number of books. The Library of Congress is the official research library of the United States Congress.
what is the star nearest to the earth
The Sun is the closest star to Earth, about 93 million miles away. The Sun's nearest neighbor, Alpha Centauri, is actually a triple-star system —three stars bound together by gravity. Alpha Centauri A and B are two bright, closely orbiting stars with a distant, dim companion, Proxima Centauri.
why do people have different skin colors
The actual skin color of different humans is affected by many substances, although the single most important substance is the pigment melanin. Melanin is produced within the skin in cells called melanocytes and it is the main determinant of the skin color of darker-skinned humans.
how do crickets make sound
The bottom of a cricket wing is covered with teeth-like ridges that make it rough. The upper surface of the wing is like a scraper. When crickets rub the upper and lower parts of their wings together, they create a chirping sound called "stridulating."
Who built the White House after the War of 1812?
The building took eight years to build and the first President to live in The White House was John Adams. The building remained as is until 1814, when it was burned during the War of 1812. After the fire, James Hoban, the original architect, was commissioned to lead the rebuilding of the White House.
how deep is the ocean? The deepest part of the ocean is called the ___________ Deep and is located beneath the ___________ ___________ Ocean in the southern end of the ___________ ___________ , which runs several hundred kilometers ___________ of the U.S. territorial island of ___________ . Challenger Deep is approximately ___________ feet deep recored on Oct 10, 2017
The deepest part of the ocean is called the Challenger Deep and is located beneath the western Pacific Ocean in the southern end of the Mariana Trench, which runs several hundred kilometers southwest of the U.S. territorial island of Guam. Challenger Deep is approximately 36,200 feet deep.
how deep is the ocean in miles? The deepest part of the ocean is in the ___________ ___________ (sometimes called the ___________ ___________ ), located in the western Pacific Ocean. At its deepest part, it's just under ___________ miles ___________ miles / ___________ km / ___________ meters deep
The deepest part of the ocean is in the Mariana Trench (sometimes called the Marianas Trench), located in the western Pacific Ocean. At its deepest part, it's just under 7 miles (6.831 miles / 10.994 km / 10,994 meters) deep
who was the first comic book superhero
The earliest superhero I could find reference to was Mandrake the Magician, who debuted in 1934, four years before Superman, who was probably the first popular superhero. Mandrake's super power was his ability to "make people believe anything, simply by gesturing hypnotically"
When was the first comic book created?
The first modern comic book, Famous Funnies, was released in the United States in 1933 and was a reprinting of earlier newspaper humor comic strips, which had established many of the story-telling devices used in comics.
first rocket in space
The first rocket which could fly high enough to get into space was the V2 missile which was first launched by Germany in 1942. The first rocket which actually launched something into space was used to launch Sputnik, the first satellite, on October 4, 1957. The rocket that launched Sputnik was a R-7 ICBM rocket.
how do bubbles get in fizzy drinks
The fizz that bubbles up when you crack open a can of soda is carbon dioxide gas (CO2). Soft drink manufacturers add this tingling froth by forcing carbon dioxide and water into your soda at high pressures—up to 1,200 pounds per square inch.
when was the choloacte bar invented
The history of candy bars actually began back in 1847. The first chocolate bar was made in Britain by Joseph Fry and his son, who pressed a paste made of cocoa powder and sugar into a bar shape. The chocolate bar was further developed in 1849 when John Cadbury introduced his brand of the chocolate bar.
what causes tornadoes
The intense spinning of a tornado is partly the result of the updrafts and downdrafts in the thunderstorm (caused by the unstable air) interacting with the wind shear, resulting in a tilting of the wind shear to form an upright tornado vortex.
what is the largest organ in the body
The largest internal organ is the liver. It is also the heaviest organ, with an average of 1.6 kilograms (3.5 pounds). The largest external organ, which is also the largest organ in general, is the skin. The longest muscle is the sartorius muscle in the thigh.
what makes the leaning tower of pisa lean
The leaning of the Tower of Pisa comes into the story in 1173, when construction began. Thanks to the soft ground, it had begun to lean by the time its builders got to the third story, in 1178. Shifting soil had destabilized the tower's foundations.
what is the strongest muscle in the body
The strongest muscle based on its weight is the masseter. With all muscles of the jaw working together it can close the teeth with a force as great as 55 pounds (25 kilograms) on the incisors or 200 pounds (90.7 kilograms) on the molars. The uterus sits in the lower pelvic region.
how tall is the world's tallest tree? The tallest trees in the world are ___________ (Sequoia sempervirens), which tower above the ground in ___________ . These trees can easily reach heights of ___________ feet (91 meters). Among the redwoods, a tree named ___________ ___________ them all. The tree was discovered in 2006, and is ___________ feet (115.7 m) tall. nts: you coul look outside a 30 stories high and still not see the top.
The tallest trees in the world are redwoods (Sequoia sempervirens), which tower above the ground in California. These trees can easily reach heights of 300 feet (91 meters). Among the redwoods, a tree named Hyperion dwarfs them all. The tree was discovered in 2006, and is 379.7 feet (115.7 m) tall.
what is the hottest place on earth
The title of "world's hottest place" is often bestowed upon El Azizia, Libya, where the highest temperature ever measured on Earth was recorded, but a study of satellite temperature data shows that the crown belongs elsewhere, and that it can shift from year to year. 'Aziziya is a town in Libya
how many languages are spoken in the world today
There are roughly 6,500 spoken languages in the world today. However, about 2,000 of those languages have fewer than 1,000 speakers. The most popular language in the world is Mandarin Chinese. There are 1,213,000,000 people in the world that speak that language.
Why does Mail need a stamp?
To mail a letter, you do not need to visit the Post Office as long as you have postage stamps, access to a postage meter or can print postage online from a company like Stamps.com. Simply address your envelope, affix postage to the upper right corner and drop it in a collection box or hand it to your mail carrier.
who is walt disney
Walter Elias "Walt" Disney was born on December 5, 1901, in Hermosa, Illinois. He and his brother Roy co-founded Walt Disney Productions, which became one of the best-known motion-picture production companies in the world. Disney was an innovative animator and created the cartoon character Mickey Mouse.
why do my cheeks get red in the winter
Well, this is called vasoconstriction, and it's caused when our bodies react to being cold by attempting to reduce blood flow to the body's surface. What actually happens to cause your cheeks to turn red, though, is when the blood vessels in your face dilate and then literally burst after narrowing
why do my muscle ache after exercise
When muscles are required to work harder than they're used to or in a different way, it's believed to cause microscopic damage to the muscle fibres, resulting in muscle soreness or stiffness. DOMS is often mistakenly believed to be caused by a build up of lactic acid, but lactic acid isn't involved in this process.
why do i get hiccups
When the air rushing in hits your voice box, your vocal cords close suddenly and you're left with a big hiccup. Some things that irritate the diaphragm are eating too quickly or too much, an irritation in the stomach or the throat, or feeling nervous or excited. Almost all cases of the hiccups last only a few minutes.
why does a match light up
When the match head is dragged along the striking surface, the sand and powdered glass cause friction and heat, which is enough to convert some of the red phosphorous to white phosphorus-a chemical so volatile that it ignites in the air.
what is the difference between a comet and a shooting star
When they hit the atmosphere, meteors rub against air particles and create friction, heating the meteors. The heat vaporizes most meteors, creating what we call shooting stars. ... The key difference is that meteor showers occur when the Earth plows into the trail of particles left behind by a comet or asteroid.
what causes an allergy
When you're exposed to the allergen again, these antibodies can release a number of immune system chemicals, such as histamine, that cause allergy symptoms. Common allergy triggers include: Airborne allergens, such as pollen, animal dander, dust mites and mold.
if the earth is moving why can't we feel it
Why can't we feel Earth's spin? We can't feel Earth's rotation or spin because we're all moving with it, at the same constant speed. Earth spins on its axis once in every 24-hour day. At Earth's equator, the speed of Earth's spin is about 1,000 miles per hour (1,600 kph).
how does a parachute work
With parachutes, it's the slowing-down effect that we want. If you fall from a plane without a parachute, your relatively compact body zooms through the air like a stone; open your parachute and you create more air resistance, drifting to the ground more slowly and safely—much more like a feather.
what is the world's highest waterfall
World's Highest Waterfall. Angel Falls (Salto Ángel) in Venezuela is the highest waterfall in the world. The falls are 3230 feet in height, with an uninterrupted drop of 2647 feet. Angel Falls is located on a tributary of the Rio Caroni.
how much would i weigh on the moon
Your weight on the Moon is 16.5% what you would experience on Earth. In other words, if you weighed 100 kg on Earth, you would weigh a mere 16.5 kg on the Moon. For you imperial folks, imagine you tipped the scales at 200 pounds. Your weight on the Moon would only be 33 pounds
what is the loch ness monster
a Scottish folklore. a couple claimed that they saw a dinosaur-like monster in loch ness, a lake in Scotland. there has been many sighting of "nessie" but none have been poven.
what is a meteor
a small body of matter from outer space that enters the earth's atmosphere, becoming incandescent as a result of friction and appearing as a streak of light.
what is ESP
also called sixth sense or second sight, includes claimed reception of information not gained through the recognized physical senses, but sensed with the mind.
what is a tidal wave
an exceptionally large ocean wave, especially one caused by an underwater earthquake or volcanic eruption (used as a nontechnical term for tsunami). -a widespread or overwhelming manifestation of an emotion or phenomenon. "a tidal wave of crime"
why do zebras and tigers have stripes?
camouflage to help them hide. stripped coats are harder to see in the light and dark shadows of the forest and grasslands.
are feet ticklish
nerve ending are what makes us feel ticklish and the more nerve ending there are in a particular spot, the more ticlish it is. our feet have the most nerve ending so they are the most ticklish of them all.
what is acid rain
rainfall made sufficiently acidic by atmospheric pollution that it causes environmental harm, typically to forests and lakes. The main cause is the industrial burning of coal and other fossil fuels, the waste gases from which contain sulfur and nitrogen oxides, which combine with atmospheric water to form acids.
who wrote the happy birthday song
the hill girls, Mildred and patty wrote " good morning to you' in 1893. the song was not a big hit until someone changed the words at a birthday party. no one knew who made the change.
why can't i see in the dark?
the human eye uses light to see. light bounce off your surrounding and into your eyes through your pupil, the black whole at the center. a picture forms on your retina, the lining at the back of your eye. your brain makes sense out of what it see. without light there is nothing to enter the retina and start the whole process.
what is greenhouse effect
the trapping of the sun's warmth in a planet's lower atmosphere due to the greater transparency of the atmosphere to visible radiation from the sun than to infrared radiation emitted from the planet's surface.
what makes a rattlesnake's tail rattle
the vibration of shell-like rings on the end of its tails. the rattle is made up of dry, hard piecies of unshade skin. as the snake grows, the number of rings increase. so,the louder the rattle, the bigger the snake. the snake will shake its rattles to tell an intruder to..... "take off!"
why can i drink something hot, but if it spilled the same thing on myself, it would burn?
your mouth has air conditioning! as you sip a hot liquid, air comes your mouth along with it and cols the drink. your saliva mixes in and cools it further.but hot stuff on your skin is just plain hot
