Many students with microbiology subjects often ask me about what happens to organisms during gram staining and what makes an organism gram-positive or negative. As I scan the net for nice resources, I stumbled upon this You Tube video answering the aforementioned questions. I do not know who exactly made this but he did a good job. It gives a nice explanation of gram staining which students can grasp better.
Part 2 is below.
I hope these videos will give students a clearer picture of gram-staining.