I read or watched a documentary a long time ago that explained that the particles in any given object are constantly being exchanged with particles in the surrounding environment. i.e. the particles of matter that make up a table are constantly being added to and taken away, exchanged with the environment, so that the table has none of the same particles over time that it originated with. I'm wondering if anyone knows anything about this and can point me in the direction of more information about it. Also, if anyone knows of any sources on the topic of how the particles in the table keep themselves in the shape of the table, that information would be useful as well. Thank you. This is my first post here and am thankful for any comments.