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Why are you watching the popcorn bowl? I'm waitingfor the next kernel to pop.
It looks like a tiny, very quiet piece of corn.And then suddenly it becomes a snack.
Welcome to Curious English from Your EnglishToolbox.
Today we are asking a small kitchen question. Whydoes popcorn pop?
Make a prediction before we explain. Is the keyingredient the heat, the water inside,
or the hard outer shell? It is the combination ofall three.
Before we explain, let us make four importantwords clear. A kernel is one single seed of corn.
For example, one kernel popped before the rest.
Starch is a natural material found in foods suchas corn, rice, and potatoes.
For example, bread and potatoes both containstarch.
A shell is a hard outer covering that protectssomething.
For popcorn, the scientific word for its shell ishull.
For example, a nut's shell protects the part weeat.
Moisture means a small amount of water inside oron something.
For example, a dry sponge has little moisture.
Now these four words will help us understand whathappens inside the kernel.
A popcorn kernel contains a small amount of watersurrounded by starch.
A tough outer hull holds the contents inside.
That tough hull acts like a tiny naturalcontainer.
As the kernel heats up, the water inside getshotter. Some of it turns into steam.
The steam cannot escape easily through the stronghull.
So pressure builds up inside. To build up means toincrease gradually.
Eventually, the hull breaks open.
The hot starch expands and quickly cools into thewhite shape we eat.
That is why a pop can sound so dramatic.
The kernel bursts open.
03:00
To burst open means to break open suddenly.
Popcorn also needs enough moisture inside thekernel.
If a kernel becomes too dry, it may not pop well.
That small amount of water is vital.
It is not the same as pouring water into the pan.
Right. The important water is already inside thekernel.
Let us review our three expressions.
Pressure can build up. A shell can burst open.
And the kernel needs enough moisture.
Your turn.
When steam cannot escape, what gradually increasesinside the kernel?
Pressure builds up.
What does the kernel do when its shell breakssuddenly?
It bursts open.
And what does a kernel need enough of to pop well?
Moisture.
On our episode page, practice these four wordswith an example for each one.
You will also find a quick check to test what youremember.
The link is in the description.
Keep your English curious.
And do not stare at the bowl too intensely.
