Average vertical velocity at different heights of the photosphere of the host granules during the emergence of their associated magnetic flux sheet. The box plots display the full distribution (scatter points), maximum and minimum values (whiskers lines), the interquartile range (box), upper and lower quartiles (box boundaries), and the median value (line within the box) for each height: low photosphere (blue box), middle photosphere (white box), and high photosphere (red box).