Asked by: Mohammad Rashid, Wakefield
A sneeze begins with a sudden inhalation. This is the ‘Aaah’ part of the sneeze. The ‘Choo!’ occurs on the exhale because most of the muscles in your body are reflexively contracting. This clamps your mouth shut until the pressure in your lungs rises too high and the air escapes in a burst. Since your tongue is pressing against the roof of your mouth, the air makes a ‘ch’ sound, and with your lips pursed, it emerges as an ‘oo’.