There are several possible reasons why your popcorn kernels didn't pop in the microwave:
Expired popcorn kernels: Popcorn kernels have a limited shelf life, and if they were too old or expired, they might not pop properly. Check the expiration date on the package and ensure your kernels are fresh.
Inadequate moisture content: Popcorn kernels need a certain level of moisture inside the kernel to build up pressure and eventually pop. If the kernels were stored in a very dry environment, they might not have enough moisture left to pop effectively.
Incorrect microwave settings: Microwave ovens vary in power, so the popping time might differ. If the microwave power was set too low, the kernels might not have had enough heat to pop. Conversely, if the power was set too high, they could burn before popping.
Improper container or cover: The container you used to pop the popcorn might not have been suitable. It's essential to use a microwave-safe container with a microwave-safe cover or microwave-safe popcorn bags designed for this purpose. These containers and bags are designed to trap steam and heat to promote popping.
Insufficient kernels: If you put too few popcorn kernels in the container, they might not generate enough pressure to pop. Aim to cover the bottom of the container evenly with kernels, leaving some room for expansion.
Poor storage conditions: If the popcorn kernels were exposed to humidity or moisture before use, they might have absorbed too much moisture, making them less likely to pop.
Contaminants: If there were any contaminants or oils inside the container or on the popcorn kernels, they might have interfered with the popping process.
To increase your chances of successful popcorn popping, ensure you're using fresh popcorn kernels, a microwave-safe container with a suitable cover, and that the kernels are stored in a dry and cool place. Additionally, experiment with different microwave power settings and popcorn quantities to find the right combination for your specific microwave oven.