What is internal solid state drive (ssd) ?

This is how our IT tech at the hospital I work explains it.

A typical hard drive stores information by writing it on a disk, like a CD

Whereas a SSD stores information using binary code and writing 1s and 0s into areas like 'rooms' and when they are full the 'door' shuts and the information is safe

This is why SSDs are becoming more popular as it is less likely for information to be damaged on one versus an older disk style hard drive.