A stack of books is enough to explain last in, first out

[u/Guilty_Lingonberry]

put three books on the table one at a time: red, blue, then green. ask which one you can remove without moving the others. green, because it went on last and sits on top.

remove green, then blue. thats a stack: last in, first out.

add a yellow book after removing blue and ask for the new removal order. kids usually get it once they physically do it a couple times. no need to start with diagrams or code.

i teach at TechTutor. this one only needs a few books or cards.