Many of the Minute Physics videos are good, but I like this one in particular because it is the best resource I have found for this challenging concept.  They show an excellent computer simulation of a cloud of gas that represents the Solar Nebula collapsing to form a proto-planetary disk.  This is a concept illustrated in just about every introductory astronomy textbook, but it is almost impossible to get the details right in an illustration.  I searched for an animation or video that shows how a collapsing cloud flattening out into a disk, and this one does not sweep the important details under the rug.  It directly addresses the NGSS middle school Earth and Space disciplinary core idea -- "The solar system appears to have formed from a disk of dust and gas, drawn together by gravity".