Molecules are made of atoms. Atomic nuclei are made of neutrons and protons. And the neutrons and protons are made of quarks and gluons. Many physicists think that this is not the end of the story, but that quarks and gluons are made of even smaller things, for example the tiny vibrating strings that string theory is all about. But then what? Are strings made of smaller things again? Or is there a smallest scale beyond which nature just does not have any further structure? Does nature have a minimal length? This is what I talk about in this video. I explain why many physicists think that nature indeed has a minimal length, which is the so-called Planck length, named after Max Planck. In this paper you can find more arguments for why the Planck length plays a special role in nature: Six easy roads to the Planck scale Ronald J. Adler https://arxiv.org/abs/1001.1205 Max Planck's paper from 1899 is here: http://bibliothek.bbaw.de/bibliothek-digital/digitalequellen/schriften/anzeige/index_html?band=10-sitz/1899-1&seite:int=454 You find a translation of the paragraph that I am referring to here: http://backreaction.blogspot.com/2007/07/planck-scale.html You can help finance my videos by donating here: https://www.paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_id=QZ6QCBQYUMJEG&source=url