Chemists and physicists shed light on a crucial aspect of friction: how things begin to slide. Using fluorescence microscopy and dedicated fluorescent molecules, they are able to pinpoint how and when the friction at the contact between two objects is overcome and sliding starts to occur. They report on the details of this important transition from static to dynamic friction.Chemists and physicists shed light on a crucial aspect of friction: how things begin to slide. Using fluorescence microscopy and dedicated fluorescent molecules, they are able to pinpoint how and when the friction at the contact between two objects is overcome and sliding starts to occur. They report on the details of this important transition from static to dynamic friction.