Water travels silently through the soil

Water in soil rises upward at millimeter-per-second speed thanks to capillary forces, migrating from dry layers toward moist regions. This movement is invisible to the naked eye, yet a plant root perceives it at every moment, binding its survival in arid periods to this invisible flow. If we could see this movement, we would notice millions of delicate water lines passing through the soil like an underground city network beneath the ground.