It was a project 20 years in the making. Finally, retired chemistry teacher Bro. Martin Sellner has finished his embroidery of the periodic table of elements. Much to the delight of netizens, the ...

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 ...