Why Do My Ears Pop When I Go Through a Tunnel in a Train or an Aeroplane?

The winners of the Naked Scientists Big Brain of the Week award this week are our astronomer Rosemary Williams and our expert in global health, Jonathan Kennedy. George wonders why my ears go pop when I go through a tunnel in a train or on an aeroplane when I'm going up down in the air. What it seems is that there's obviously a difference in air pressure in a cabin in an Aeroplane. But your ear's got a brilliant mechanism for balancing out equalizing the pressure on both sides. The Ustation Tube vents, as it were, It vents the middle ear out back to the normal atmospheric external pressure through your nose.