Note: This video is designed to help the teacher better understand the lesson and is NOT intended to be shown to students. It includes observations and conclusions that students are meant to make on ...

Note: This video is designed to help the teacher better understand the lesson and is NOT intended to be shown to students. It includes observations and conclusions that students are meant to make on ...

I suspect that a lot of you readers share with me a lifelong fascination with the Periodic Table of Elements. I'm not sure where I first saw it -- I think maybe it was a poster on the wall of my fifth ...