Teach the Periodic Table to elementary kids.
Most kids as well as adults know little to nothing about the Periodic Table of elements unless they study chemistry.
I encourage you to introduce the Periodic Table to elementary kids, even kinder kids.
The Periodic Table is not to be memorized, instead, it is to be used.
Every element known to man is listed on this table. Each element has its own specific place on the table.
You will find one of if not the best free printable Periodic Table materials here http://elements.wlonk.com/index.htm