Question

name
day 4 weekly question
what makes popcorn pop?
in order for popcorn to pop, energy must be applied to the kernels. this energy may take the form of thermal energy, such as when popcorn is popped on the stove or in an air - popper. or it may take the form of radiant energy, which is energy emitted as electromagnetic waves or particles. this is how popcorn is popped in a microwave oven.
when an outside source of energy is applied to a kernel of popcorn, thermal energy in the kernel increases as the molecules of water in the starch vibrate. the temperature of the kernel increases and the water molecules move faster and farther apart, until the water turns to steam. but because the hull is waterproof, the steam cant escape, and the pressure builds. the starch liquefies, increasing the pressure even further. ultimately, the pressure becomes so intense that the hull gives way. the starch and steam come bursting out of the kernel, turning it inside out. as this happens, the jelly - like starch expands into bubbles that freeze upon contact with the air, forming the characteristic spongy white blobs we all know and love.
number the events below in the correct order to explain how popcorn pops.
____ the kernel explodes.
____ energy is applied to the popcorn kernel.
____ pressure builds within the kernel.
____ the bubbling starch freezes.
____ thermal energy within the kernel increases.
168 big idea 6·week 2
daily science·emc 5016·© evan moor corpora

Explanation:

1. Identify the starting event: energy is first applied to the kernel.
2. Trace the energy transfer: applied energy raises thermal energy in the kernel.
3. Track pressure change: trapped steam/starch builds internal pressure.
4. Note the breaking point: pressure causes the kernel to explode.
5. Identify the final step: exploded starch freezes in air to form popped corn.

Answer:

1. The kernel explodes.
2. Energy is applied to the popcorn kernel.
3. Pressure builds within the kernel.
4. The bubbling starch freezes.
5. Thermal energy within the kernel increases.