Obviously, this explanation while colorful and entertaining is not what really happens! Actually, each popcorn kernel contains a minute amount of water inside a circle of starch which is then surrounded by the hard outer surface of the kernel.

With heating, the water expands and with the corresponding pressure building against the starch it eventually pushes through the hard surface making the popcorn burst open. As this process occurs, the soft starch inside the kernel inflates and bursts turning the kernel inside out and the popcorn is now popped.
Now on to choosing a good popcorn popper, we want to look for poppers which have gone under scientific lab testing and are proven to do a great popping job by producing maximum volume of popcorn with minimal waste.

Another consideration will be whether children are going to operate the popper. You will want to look for easy to follow instructions and be sure that the popper is not too heavy for the child to handle.
Also, be aware of some convenience features that will make the job of popping easier such as an oil line for easy measuring, dishwasher safe covers, easy cleaning surface, and a signal light to indicate when done.

The popper should also allow for steam to escape during the popping cycle. This will keep the popcorn from becoming soggy and will reduce the chance of the person operating the popper getting splattered with hot liquid when the cover is taken off. These steam releases will vary from popper to popper. Some will have small vents, some covers are designed to fit into a ridge around the base of the popper with enough clearance for steam to be released. Be sure that the popper has this feature.

Before you buy, be sure you know whether or not an electric popper is automatic or non-automatic. An automatic popper contains a thermostat that automatically shuts off the heating element at the end of the popping cycle. With a non-automatic popper you will have to watch more closely to prevent burning the popcorn once the cycle is complete. These poppers must be promptly disconnected. Be sure to check the label for this information.