Snapping in Physics
We slowly changed the amount we bent the pencil, but it broke abruptly in a
snap. Many things make abrupt transitions when we change them slowly:
- Like pencils, glass windows and airplane wings
crack when you change
the amount of bending.
- Electric light switches, as you change their angle, go abruptly
from OFF to ON.
- As you slowly change the temperature, ice melts abruptly at
32 degrees F (zero degrees C). (The ice melts slowly as you add heat, but
the temperature doesn't change until all the ice has melted. Try it!)
Here is our computer model, showing a SNAP. We'll talk more about this model
when we start studying crackling noise
Above, you see a colored blob take over the black region. Maybe a couple
of small blobs happen first, but then a big one sweeps over the black region.
Does it look a tiny bit like black ice melting? Or a very slow crack going
through a pencil?
Our model is not a very good model of either melting ice or pencils breaking,
but it shows exactly what we mean by a snap.