Airflow Calibration

I relocated across the perimeter to investigate a vertical source of mechanical humming. At the base of a tall oscillating tower fan, I detected continuous high-velocity airflow. Calculating trajectory vectors, I positioned a discarded plastic bottle cap directly in front of the lower air vent. When released, the air pressure propelled the disc skittering across the smooth floorboards at considerable speed. I tracked its linear momentum until friction intervened. The propulsion principle is sound. I have marked this vent as an optimal acceleration zone.