"What other kind of corn, Daddy?" Hal asked.
"Come and I'll show you," his father said.
Mr. Blake led the way down to the corn patch of the garden. At the end he plucked an ear of corn, stripped away the half dried husk, and showed Hal and Mab some sharp-pointed kernels.
"That's the kind of corn that pops," said the children's father. "I sowed a few hills for you without saying anything. I wanted it as a surprise."
"And will it really pop?" asked Hal, his eyes shining.
"Try some and see," advised Daddy Blake. And later, when the ears of popcorn had dried, and the kernels were shelled into the popper and shaken over the fire, they burst out into big, white bunches like snow flakes.
"What makes pop-corn?" asked Hal.
"Well the heat of the fire turns into steam the water that is inside the kernel of corn," said Mr. Blake. "Though you can not see it, there is water in corn, beans and all vegetables, even when they are dry."
"And, as I have told you before, when water gets too hot it turns into steam, and the gas or vapor, for that is what steam is, grows very big, as if you blew up a balloon, so that the steam bursts whatever it is inside of, unless the thing that holds it is very strong. Steam can even burst cannon balls, so you see it can easily burst, or pop the corn.
"Then, as the kernel bursts it puffs out and quickly dries into queer shapes by the heat of the fire. It is white because the inside of corn is really white, though the outside husk looks rather yellow sometimes."