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 ...

A century and a half ago, a Russian chemistry professor published a classification of all the known elements, organized by atomic weight. Today, the system that he created for his students — plus some ...

In India, children under 16 returning to school this month at the start of the school year will no longer be taught about evolution, the periodic table of elements or sources of energy. Overall, the ...