Last year while attending the Biennial Conference on Chemical Education at GVSU I had the opportunity to hear a talk that showed a video of a chemical demonstration showing the burning of magnesium metal. We have all seen many of these videos (thank you YouTube) and probably have performed this demo for our own students many times. During the video it may have been represented with a chemical equation followed by the students being asked to balance the equation or maybe even predict the products. Although the use of video including the showing of the equation nicely represents the macroscopic and symbolic representation, what was so unique about this particular video is that it also included the particulate representation embedded on top of the video of the demo. This was the first time I had seen the particulate level representation done like that and so I was intrigued in wanting to find more of these representations. One of my favorite videos that represents the three so-called worlds (macroscopic, symbolic, particulate) beautifully is this one entitled HCl+NH3=NH4Cl - Ammonium chloride smoke under 100,000,000x microscope from MEL Science on Youtube. Since wanting to incorporate more of these videos into my lesson plans I was thrilled when I met up with Dave Doherty @AtomsNMolecules and he shared with me the Atomsmith Molecule Lab for the iPad. This was the first time I had seen 3D models of chemical reactions represented this way. Having the capability to move a slider back and forth to show the progression from reactants to products using 3D models and then having the capability with the program to link to real world videos representing the reaction again shows the power of this program. If you know of more of these types of videos showing these representations then please share in the comments below or on twitter using @ChemEdX.