Question: Which type of popcorn kernel is pointed on both ends?
About the article "Popcorn", section "Expansion and yield".

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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.
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 both these reasons, higher-expansion popcorn fetches a higher profit per unit weight.
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 at all will decline.
When the popcorn has finished popping, sometimes unpopped kernels remain.
Known in the popcorn industry as "old maids", the kernels don't pop because they do not have enough moisture to create enough steam for an explosion.
Rehydrating prior to popping usually results in eliminating the unpopped kernels.
Popcorn varieties are broadly categorized by the shape of the kernels, the color of the kernels, or the shape of the popped corn.
While the kernels may come in a variety of colors, the popped corn is always off-yellow or white as it is only the hull (or pericarp) that is colored.
"Rice" type popcorns have a long kernel pointed at both ends; "pearl" type kernels are rounded at the top.
Commercial popcorn production has moved mostly to pearl types.
Historically, pearl popcorns were usually yellow and rice popcorns usually white.
Today both shapes are available in both colors, as well as others including black, red, and variegated.
Commercial production is dominated by white and yellow.
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, like amaranth grain, sorghum, quinoa, and millet, 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.
There are various techniques for popping corn.
Along with prepackaged popcorn, which is generally intended to be prepared in a microwave oven, there are small home appliances for popping corn.
These methods require the use of minimally processed popping corn.
A larger-scale, commercial popcorn machine was invented by Charles Cretors in the late 19th century.
Unpopped popcorn is considered nonperishable and will last indefinitely if stored in ideal conditions.
Depending on how it is prepared and cooked, some consider popcorn to be a health food, while others caution against it for a variety of reasons.
Popcorn can also have non-food applications, ranging from holiday decorations to packaging materials. 
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, dense type.
As the oil and the water around the kernel are heated, they turn the moisture in the kernel, which has a moisture-proof hull, into a superheated pressurized steam.
Under these conditions, the starch inside the kernel gelatinizes, softens, and becomes pliable.
The pressure continues to increase until the breaking point of the hull is reached: a pressure of about and a temperature of .
The hull ruptures rapidly, 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.
Some wild types will pop, but the cultivated strain is "Zea mays everta", which is a special kind of flint corn. 
This is a list of 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.
Microwave popcorn is a convenience food consisting of unpopped popcorn in an enhanced, sealed paper bag intended to be heated in a microwave oven.
In addition to the dried corn the bags typically contain solidified cooking oil, one or more seasonings (often salt), and natural or artificial flavorings or both.
With the many different flavors, there are many different providers. 
Popcorn is a type of maize in which the kernels expand when heated.
Popcorn may also refer to: