Popcorn is a variety of corn kernel which expands and puffs up when heated; the same names also refer to the foodstuff produced by the expansion.
Image: Popcorn Studio 2011
Image: Popcorn up close salted and air popped
An early popcorn machine in a street cart, invented in the 1880s by Charles Cretors in Chicago.
Specimen of Zea mays everta
Sweet corn, also called sweetcorn, sugar corn and pole corn, is a variety of corn grown for human consumption with a high sugar content. Sweet corn is the result of a naturally occurring recessive mutation in the genes which control conversion of sugar to starch inside the endosperm of the corn kernel. Sweet corn is picked when still immature and prepared and eaten as a vegetable, rather than field corn, which is harvested when the kernels are dry and mature. Since the process of maturation involves converting sugar to starch, sweet corn stores poorly and must be eaten fresh, canned, or frozen, before the kernels become tough and starchy.
Husked sweet corn
Loose kernels of sweet corn
Young sweet corn
The same rows of corn 41 days later at maturity