Were stretching a 13 kb DNA-construct between two optically trapped beads. This isn't a video of the experiment itself, but of some entangled beads we found in an old sample. The beads are 3 or 2 micron in diameter, and we hold on to the middle big bead with the optical trap while moving around the microscope stage. Hydrodynamic drag stretches out the chain of entangled beads. Not much, if any, scientific value, but a fun video nevertheless.