Conformations of single DNA molecules in steady shear flow at Wi = 19. Time between images is (A) 6 seconds, (B) 0.84 seconds, or (C) 6 seconds. Scale bar: 5 μm. From D. E. Smith, H. P. Babcock and S Chu, Science, 1999, 283, 1724-1727. Reprinted with permission from AAAS.