Figure 2.
Ejection of contaminated droplets (highlighted in red) triggered by the impact of a raindrop (diameter 2.5 mm, velocity 6 m s−1) on (a) a green liquid film (here in a 1 mm depth pool at the upper surface of the cantilever beam) at −2.5, 2.5, 17.5 and 62.5 ms after impact; (b) a prayer plant leaf at 6 ms after impact; (c) a strawberry leaf at 55 ms after impact; (d) a lucky bamboo leaf at −2, 4, 8, 16, 52, 61, 69 and 74 ms after impact. In (b–d), a sessile drop containing pathogen analogue (red dye) is initially placed close to the impact point. Scale bars, 1 cm. See electronic supplementary material, movies S1–S4.