1Two things to notice first
Grains have sizes, and shaking opens tiny gaps
You only need two ideas. Watch each one:
Grains come in sizes
A pile can be all one size, or a mix of big and small. A big bead and a tiny bead sitting next to each other are still both just grains in the pile.
Shaking opens gaps
Each shake makes the whole pile jiggle and lift for a split second. In that moment, tiny gaps open up between the grains — then everything drops back down.
2Two kinds of pile
The matched pile vs the mismatched pile
We will compare two starting mixtures. In this model, the colors only help us track the grains; size is the property that differs.
The matched pile
Both colors have the same size. Any gap that fits one color also fits the other.
The mismatched pile
Some openings can fit a small bead but not a large one. What could repeated openings do to a whole mixed pile?
3Your turn — shake the jar
Turn the shaking up and watch the grains jiggle
Here's a jar with big coral grains and small teal grains all mixed up. Slide the shaking from gentle to hard and watch the whole pile come alive — feel how shaking just makes everything jiggle.
4Now run the real test
Two mixtures. The same four jolts.
Compare both jars side by side. Their colors start mixed. Predict whether a size difference changes what repeated shaking does, then give both the same four jolts.
Guess before you shake
You shake a jar of mixed big and small beads, over and over. Do they blend together more, or sort into layers?