Many people seem to find it difficult to understand how Scrum is a “framework”, so Scrum is frequently called a “process”.
When trying to explain the difference, I like to use the image of a bottle, which serves as a “framework” for water molecules. Let’s say your goal is to pour water into the bottle and then to pour it from there into a glass. The bottle serves as a framework for the stored water, making it conform to a certain shape, and when you pour out the water, the bottle’s neck becomes the framework for the flowing water, making it flow into a certain direction.
In the end, you have achieved your goal of getting the water into the glass. However, you have never attempted to exert control over single water molecules. You have not tried to determine where each molecule will be located in the bottle and you have not attempted to make them leave the bottle and enter the glass at a specific point in time. You have only given the water a framework for reaching the goal, but beyond that, the water was free to self-organize. And despite the fact that the movements of the water molecules are completely chaotic and unpredictable, you would probably be quite confident that you will reach the goal.
However, if you tried to pick out the water molecules one by one, transferring them to the glass in a predetermined order – that would be a process, not a framework. And that is essentially what the (for the purpose of this metaphor not very aptly named) waterfall process is trying to do.