Process

Melting the Butter
In the first image, butter is being melted in a pot.

Thermodynamics:

• First Law (Conservation of Energy): Heat from the stove is transferred to the butter, increasing its internal energy and causing it to melt (solid → liquid).

• Second Law: Heat flows from the hot stove to the colder butter, not the other way around.

Adding Popcorn Kernels
In the second image, unpopped corn kernels are added to the melted butter. The heat will soon begin to transfer to the kernels.

Thermodynamics:

• First Law: Energy from the heat source continues to increase the internal energy of the kernels.

• Second Law: Energy flows from the hot oil/butter to the cooler kernels.

• Third Law (indirectly): As the kernels are heated, they move farther from absolute zero, increasing entropy.

Popping Process (Covered Pot)
In the third image, the pot is covered, and the kernels are starting to pop.

Thermodynamics:

• First Law: Internal energy change causes water inside the kernels to turn into steam, building pressure until the shell bursts (thermal → mechanical energy).

• Second Law: Entropy increases as ordered kernels explode into fluffy, irregular popcorn.

• Zeroth Law: If heating stops, thermal equilibrium is eventually reached between the popcorn, pot, and steam.

Adding Salt to Popcorn
In the final image, salt is sprinkled onto the freshly popped popcorn while it’s still warm.

Thermodynamics:

• First Law: Residual heat from the popcorn may slightly warm the salt, conserving energy within the system.

• Second Law: Energy flows from the warmer popcorn to the cooler salt. Entropy continues to increase as the system moves toward equilibrium.