Now there’s a familiar
bit of everyday wonder —
dandelion seeds in flight.
Just blow on a dandelion head
and watch the tufts separate
and drift off — a block,
a mile, maybe 50 miles.
So how do they do it?
Scientists knew
that it all depended
on the intricate structure of
the seed’s fluffy top,
known as a pappus.
But how did it work?
Like a balloon, or
a wing
or something
completely different?
To find out, researchers
used a small wind tunnel
to mimic a falling seed.
They recorded in
great detail how
the air flowed through
and around the pappus.
What they discovered
was a vortex
never seen before in nature.
As air moved
around and through
the parachute-like top
of the dandelion seed,
the complex interaction
of air currents
eventually formed a vortex.
And that swirl of air
created a low-pressure area
that helped hold the seed
up, allowing it to travel
long distances on the wind.
To test the idea
that empty space was
the key to the
vortex, the scientists
constructed artificial
dandelion seeds —
tiny silicon discs with
lots of empty space.
Sure enough, the exact
same vortex appeared.
Understanding how the
complexities of air flow
support the flight
of dandelion seeds
could offer clues on how to
create minuscule drones —
so-called smart dust.
But just for now, you can
think of dandelion seeds
as flying at the intersection
of efficiency and beauty.
