Question CSS box model: padding and margin

Hello everybody!

I am currently learning the box model for web design session (https://www.codecademy.com/paths/web-development/tracks/getting-more-advanced-with-design/modules/learn-css-box-model/lessons/box-model-intro/exercises/box-model-review).

I was wondering whether the padding of an element is the same as the margin of one of its child element --supposing it has children.
I can’t see the difference between the two watching at the box model diagram: https://s3.amazonaws.com/codecademy-content/courses/freelance-1/unit-4/diagram-boxmodel.svg

Thank you for your help,

Best regards,

Alexandre