question: Why does a popcorn pop while others corn do not?
comment: Popcorn is harder than other corn kernels. The outside keeps water from escaping, causing kernels to explode. Other grains like sorghum and quinoa will pop though!
passages: List of popcorn brands
  
  This is a list of notable popcorn brands. Popcorn, also known as popping corn, is a type of corn (maize, "Zea mays var. everta") that expands from the kernel and puffs up when heated. Popcorn is able to pop because its kernels have a hard moisture-sealed hull and a dense starchy interior. Pressure builds inside the kernel, and a small explosion (or "pop") is the end result. Some strains of corn are now cultivated specifically as popping corns.
   As the oil and the water within the kernel are heated, they turn the moisture in the kernel into pressurized steam. Under these conditions, the starch inside the kernel gelatinizes, softens, and becomes pliable. The internal pressure of the entrapped steam continues to increase until the breaking point of the hull is reached: a pressure of approximately and a temperature of . The hull thereupon ruptures rapidly and explodes, causing a sudden drop in pressure inside the kernel and a corresponding rapid expansion of the steam, which expands the starch and proteins of the endosperm into airy foam. As the foam rapidly cools, the starch and protein polymers set into the familiar crispy puff. Special varieties are grown to give improved popping yield. Though the kernels of some wild types will pop, the cultivated strain is "Zea mays everta," which is a special kind of flint corn.
   The corn grown by Kelty was never hybridized or genetically modified. Kelty's stalks would reach a height of four to five feet. Each kernel was capable of producing four to six stalks with three to four ears of corn each, unlike field corn. Each ear of corn was grown to be less than three inches long. The characteristics of Kelty's popcorn were created through open pollination, seed selection, and roguing.
  
  Section::::History.:Mealhow purchase.
   Popcorn will pop when freshly harvested, but not well; its high moisture content leads to poor expansion and chewy pieces of popcorn. Kernels with a high moisture content are also susceptible to mold when stored. For these reasons, popcorn growers and distributors dry the kernels until they reach the moisture level at which they expand the most. This differs by variety and conditions, but is generally in the range of 14–15% moisture by weight. If the kernels are over-dried, the expansion rate will suffer and the percentage of kernels that pop will decline.
   Popping results are sensitive to the rate at which the kernels are heated. If heated too quickly, the steam in the outer layers of the kernel can reach high pressures and rupture the hull before the starch in the center of the kernel can fully gelatinize, leading to partially popped kernels with hard centers. Heating too slowly leads to entirely unpopped kernels: the tip of the kernel, where it attached to the cob, is not entirely moisture-proof, and when heated slowly, the steam can leak out of the tip fast enough to keep the pressure from rising sufficiently to break the hull and cause the pop.
   When the popcorn has finished popping, sometimes unpopped kernels remain. Known in the popcorn industry as "old maids", these kernels fail to pop because they do not have enough moisture to create enough steam for an explosion. Re-hydrating prior to popping usually results in eliminating the unpopped kernels.
   Some strains of corn (taxonomized as "Zea mays") are cultivated specifically as popping corns. The "Zea mays" variety "everta", a special kind of flint corn, is the most common of these.
  
  The six major types of corn are dent corn, flint corn, pod corn, popcorn, flour corn, and sweet corn.
  
  Section::::History.
  
  Corn was first domesticated about 10,000 years ago in what is now Mexico. Archaeologists discovered that people have known about popcorn for thousands of years. In Mexico, for example, remnants of popcorn have been found that date to around 3600 BC.
   In the popcorn industry, a popped kernel of corn is known as a "flake". Two shapes of flakes are commercially important. "Butterfly" (or "snowflake") flakes are irregular in shape and have a number of protruding "wings". "Mushroom" flakes are largely ball-shaped, with few wings. Butterfly flakes are regarded as having better mouthfeel, with greater tenderness and less noticeable hulls. Mushroom flakes are less fragile than butterfly flakes and are therefore often used for packaged popcorn or confectionery, such as caramel corn. The kernels from a single cob of popcorn may form both butterfly and mushroom flakes; hybrids that produce 100% butterfly flakes or 100% mushroom flakes exist, the latter developed only as recently as 1998. Growing conditions and popping environment can also affect the butterfly-to-mushroom ratio.
   Since 1854, the ancestors of Richard Kelty (1936-2015) had been growing a heirloom popcorn variety out of small kernels, whose hulls would disintegrate after being popped, resulting in a richer taste. The popcorn had been introduced to the Kelty family by Native Americans, who shared it with them. The Kelty family had never sold the popcorn, which was only grown for personal consumption.
   Popcorn
  
  Popcorn (popped corn, popcorns or pop-corn) is a variety of corn kernel, which expands and puffs up when heated.
  
  A popcorn kernel's strong hull contains the seed's hard, starchy endosperm with 14–20% moisture, which turns to steam as the kernel is heated. Pressure from the steam continues to build until the hull ruptures, allowing the kernel to forcefully expand from 20 to 50 times its original size—and finally, cool.
   Popping of the kernels was achieved by hand on the stove-top through the 19th century. Kernels were sold on the East Coast of the United States under names such as "Pearls" or "Nonpareil". The term "popped corn" first appeared in John Russell Bartlett's 1848 "Dictionary of Americanisms". Popcorn is an ingredient in Cracker Jack, and in the early years of the product, it was popped by hand.
   Tiny but Mighty Popcorn
  
  Tiny but Mighty Popcorn is an American brand of heirloom popcorn, introduced in 1981, when Iowa farmer Richard Kelty founded K&K Popcorn. Iowa farmers Gene and Lynn Mealhow later purchased the company in 1999, and subsequently renamed it.
  
  Section::::History.
  
  Section::::History.:Kelty family.
   Section::::Cooking methods.
  
  Popcorn can be cooked with butter or oil. Although small quantities can be popped in a stove-top kettle or pot in a home kitchen, commercial sale of freshly popped popcorn employs specially designed popcorn machines, which were invented in Chicago, Illinois, by Charles Cretors in 1885. Cretors successfully introduced his invention at the Columbian Exposition in 1893. At this same world's fair, F.W. Rueckheim introduced a molasses-flavored "Candied Popcorn", the first caramel corn; his brother, Louis Ruekheim, slightly altered the recipe and introduced it as Cracker Jack popcorn in 1896.
   In mid-2007, Corn Pops launched its first line extension in many years called "Chocolate Peanut Butter Pops". In 2012, "Cinnamon Corn Pops" were introduced.
  
  Section::::Description.
  
  Corn Pops are made from milled corn. Though the name of the cereal is 'Corn' Pops, since January 2004, its ingredients have included wheat starch, essentially making the cereal multigrain. By 2007, Coconut Oil was added to the US ingredients.
   Popcorn's accessibility increased rapidly in the 1890s with Charles Cretors' invention of the popcorn maker. Cretors, a Chicago candy store owner, created a number of steam-powered machines for roasting nuts and applied the technology to the corn kernels. By the turn of the century, Cretors had created and deployed street carts equipped with steam-powered popcorn makers.
   BULLET::::- Some varieties of maize (usually called corn in North America) are dried to produce popcorn. Popcorn kernels with a high moisture content will pop when freshly harvested, but not well, and are also susceptible to mold when stored. So, popcorn growers and distributors dry the kernels until they reach the moisture level at which they expand (pop) the most when cooked. Dried maize left on the ear is also used for decorative purposes.
  
  Section::::Fungi.
  
  BULLET::::- Baker's yeast
   Each kernel of popcorn contains a certain amount of moisture and oil. Unlike most other grains, the outer hull of the popcorn kernel is both strong and impervious to moisture and the starch inside consists almost entirely of a hard type.
   At the time of the Mealhow purchase, K&K Popcorn was sold through Fareway stores. The Mealhows were initially unsuccessful in convincing Whole Foods Market to carry their product. One store manager in Chicago ultimately agreed to stock the product for a month; the manager contacted the family 10 days later to request additional stock after it sold out. The company's popcorn was eventually carried in every Whole Foods store in Chicago. By 2000, the company's popcorn was advertised as being the world's smallest; Gene Mealhow stated, "The smaller the kernel, the better the flavor."
   Producers and sellers of popcorn consider two major factors in evaluating the quality of popcorn: what percentage of the kernels will pop, and how much each popped kernel expands. Expansion is an important factor to both the consumer and vendor. For the consumer, larger pieces of popcorn tend to be more tender and are associated with higher quality. For the grower, distributor and vendor, expansion is closely correlated with profit: vendors such as theaters buy popcorn by weight and sell it by volume. For these reasons, higher-expansion popcorn fetches a higher profit per unit weight.
   Charles Cretors traveled the Midwest and settled in Fort Scott, Kansas for a few years, and then Decatur, Illinois. He spent his time working in the painting and contracting business, opened a bakery, and eventually a confectionery shop. As each venture led to the next, Cretors discovered he had a passion for how things worked.
   Section::::Terminology.
   Popcorn (disambiguation)
  
  Popcorn, or pop corn, is a variety of corn kernel, which forcefully expands and puffs up when heated. 
  
  Popcorn , or pop corn, may also refer to:
  
  Section::::Geography.
  
  BULLET::::- Popcorn, Indiana, United States
  
  Section::::People.
  
  BULLET::::- Faith Popcorn (born 1943), futurist
  
  BULLET::::- Marvin Sutton (1946-2009), American Appalachian moonshiner known as "Popcorn"
  
  BULLET::::- Richard "Popcorn" Wylie (1939–2008), American R&B musician, songwriter and record producer
  
  Section::::Arts, entertainment, an media.
  
  Section::::Arts, entertainment, an media.:Films.
  
  BULLET::::- "Popcorn" (1991 film), a horror film
  
  BULLET::::- "Popcorn" (2007 film), a teen comedy
  
  Section::::Arts, entertainment, an media.:Literature.
  
  BULLET::::- "Popcorn" (novel), a 1996 novel by Ben Elton
   Popcorn maker
  
  A popcorn maker (also called a popcorn popper) is a machine used to pop popcorn. Since ancient times, popcorn has been a popular snack food, produced through the explosive expansion of kernels of heated corn (maize). Commercial large scale popcorn machines were invented by Charles Cretors in the late 19th century. Many types of small scale home methods for popping corn also exist.
   Section::::Uses.
  
  Section::::Uses.:Fodder (ensilaged or nonensilaged).
   Charles Cretors took his new popcorn wagon to the Midway of Chicago's Columbian Exposition in 1893 and introduced the new corn product. After a trial period where Cretors gave away samples of his new popcorn product, people lined up to purchase bags of the hot, buttered popcorn. The smell of roasting peanuts and of hot buttered corn being popped in its seasoning before the buyers' attracted attention and sales.
  
  Section::::History.:1900s through 1930s.
  