Where liquid water meets the air
it has a surface tension.
An outer layer of molecules
that all have strong attraction.

Water droplets round in shape
like beads will often form,
hanging on a cobweb’s threads
like jewels in the dawn.

And on a pond small insects simply
walk along its top.
Their tiny feet don’t break that layer.
Along the top they hop.

A raindrop on a window-pane
will slide towards the ground
as water is a fluid that
can easily move round.

It leaves behind a trailing tail
as it goes trickling past
because that surface tension makes
it stick upon the glass.

I like to pick out two big drops
and guess their moving pace
to see which one will trickle first
and win the window race.

Poem from The Science Rhymes Book. Illustration by Amy Sheehan