How do you know when they "understand"?

How many times do we ask our students: Do you get it? Do you understand? And how many times do we think they get it because they eagerly nod their heads as though they're ready to teach it themselves. And when it's time to apply the what they understand, they demonstrate that they really don't. Little did we know that they were eagerly nodding to get it the "xxxx" over wtih. Well, I think true understanding, "comprehension", or however we refer to the elusive "light going on" about any subject is when a student, or for that matter anyone, can do 3 things:

1. Articulate it in their own words,


2. Visualize it, and


3. Apply it to various contexts.

Think about it: how else can you really understand something unless you say it in the words that make most sense to you and the context of the world as you see it and live in it. Once you're able to visualize this, you are then able to apply that knowledge to endless number of situations.

The challenge that educators have is: how do we construct this for our students at any developmental stage. How do we provide the platter of appetizing strategies for them to be able to express or demonstrate their understanding on any given subject? (Food metaphors work well for me.)

I propose that we first limit this need we have to satisfy our sense of self worth by asking them what they understand and instead find the means for them to show us how they understand. What do you think?