Why Popcorn Pops
Written by Studio AM.
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A popcorn kernel is a seed with a tough outer shell. Inside it are starch and a small amount of water.
As the kernel heats, water inside becomes steam and pressure builds. The strong shell holds that pressure in while the hot starch softens.
Eventually the pressure becomes too great for the shell. It breaks, the steam bursts out, and the softened starch expands into the fluffy shape we eat. The starch then cools and sets.
The shell and moisture both matter. If too much water has escaped, there may not be enough pressure for a good pop. A damaged shell can also let steam leak away before enough pressure builds. That is why some kernels stay at the bottom of the pan.
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Questions
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Question 1 of 4
What is the main point of the passage?
The answer is C: Popcorn pops because trapped steam pushes until the sealed shell breaks.
Heating creates pressure inside the shell; its release lets softened starch expand.
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Question 2 of 4
What would most likely happen to a kernel that has fully dried out, with no water left inside?
The answer is A: It would not pop normally because no water could produce steam.
The described mechanism needs water to produce steam and pressure.
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Question 3 of 4
In this passage, "bursts" means
The answer is B: breaks out suddenly and with force
The steam escapes suddenly when the shell breaks, unlike a slow leak.
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Question 4 of 4
Why can a damaged shell prevent a good pop?
The answer is D: Steam can escape before enough pressure builds.
The final paragraph connects a damaged shell with pressure escaping too early.
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