Thank you, I understand you. You mean, show the source from where I copied it. But the fact is that the themes of my posts, not the repetition of school material and knowledge, but the logical explanation of physical phenomena, based on my observations and logical conclusions. My material is not informational but for discussion, reflection and use for research. In case I refer to well-known materials or knowledge, I always indicate the source and usually it's wikipedia, in which you can find almost all reference data if someone does not remember them.
As for this post, all images have a signature and a link to an article from Wikipedia for understanding the issue.