I certainly wouldn't want to put my nose to one of those. It'd shave off the already tiny portion of a nose I do have! Some of the other members of my family, on the other hand....might not mind so much.
Of course we all know that putting one's nose to the grindstone is a figure of speech, an idiom, meaning to work diligently at something. Because, by working diligently at something, you sharpen your skills, you become more efficient, you gain more knowledge, you have a better understanding: you become a better tool or a finer piece.
That's what a grindstone does. By rotating and applying a metal to the surface of the stone (usually sandstone), a chisel can be sharpened, for example, as in the above picture provided by google images.
So when we say we're "back to the grindstone" we mean we're back to working diligently. Or rather, that the children are back to working diligently (we hope) at school. But how many adults really and truly work diligently? So as to actually become a better tool or a finer piece?
Work ethic, gumption, "grit"--these are all qualities I believe we must encourage in our children, for without them, they will become like everyone else: satisfied with the minimum, discouraged at the first obstacle.
What good is that? Talk about not motivating.
Along with those, we ABSOLUTELY must develop the virtues of charity and honesty in our children. These are just as important, and in fact, if the charity is true charity, then all the others will flow from it. That is the trick, though--fostering a true charity. And honesty, sometimes I wonder if honesty even exists in our world anymore. But it does. In bits and pieces.
So that's your homework assignment: work ethic, gumption, "grit", charity, honesty
Be glad--you have so much to give!