Laminate Flooring is a floating floor - which means that it is not attached at any point to the subfloor. Most of the laminates today are installed without any glue (all of ours are glueless systems).
Construction of the Laminate Floor
Laminate flooring is made up of 5 different layers, they are;
Overlay. The overlay is the finish, the protective layer which makes the laminate floor so durable.
Decoration. The Decorative layer is a printed image of either wood, tile, or pretty much anything! This layer determines the look of the floor. Better quality decoration layers means a more realistic look.
High Density Fiberboard. This layer is what gives the floor it's strength. The construction of the core also determines whether or not it can be installed into high-humidity areas, like bathrooms.
Locking System. The locking system allows the floor to lock to other planks, and makes for a simple and easy install. There are many different locking systems - each with their pros and cons.
Stabilizing Layer. This is what helps (in conjunction with the High Density Fiberboard - HDF core) with stability. This will make sure that the floor will stay together and not fall apart in different humidity conditions.
On the short term, most laminates are considered more durable than hardwood - as it takes more to scratch and dent than it would a wood floor.
You can compare the different laminates based on their AC Level - which, depending on who you talk to either means Abrasion Coefficient, or Abrasion Class.
The scale ranges from AC1 all the way up to AC6 (which is new). The higher the number, the more durable and able to withstand wear.