I learnt something shocking today

Here I'm in my forties, thinking nothing much can shock me
but today I got a shock of huge proportions.
I always thought propellors were old fashioned sort of keys,
used to start a motor: spun contortions.
My husband and my son have been in fits of disbelief,
that I should be so ignorant. But how
is someone meant to know about the airflow-engine thing
if physics-phobia made me like a sow-
(pig-headed in my inattention to anything like engines).
I'm trying now to slot this knowledge in
and keep it in a place I won't ignore. But I'm afraid I will forget,
reverting to original dumb sin.

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