- [Marten] The ice is typically around 5 centimeters
when I skate on it.
That sound you hear is actually
a combination of two sounds.
It's the sounds from cracks striking beneath me
and the vibrations within the ice plate itself.
It sounds like it's something super sonic.
(bright upbeat music)
(skates swooshing)
- Meet Märten Ajne. - Hi I'm Märten Ajne.
- [Narrator] He's a mathematician
who enjoys riskier hobbies than most.
- [Marten] I been skating on thin ice for 40 years.
- [Narrator] When he's skating though,
he's also listening.
- [Märten] The thinner the ice, the higher the pitch.
Just about when the ice is to break
and that will be about 3 centimeters,
the pitch is at the highest singing.
There's a reportedly highest note
of the Soprano singing.
- [Narrator] Märten relies
on his knowledge as a mathematician
to calculate the thickness of the ice,
its flexibility and its temperature.
- [Märten] Many people tend to freak out
when they see us skating on thin ice,
but I couldn't be more calm because I know what I'm doing.
Sometimes the ice is perfectly clear
and I can see fish below,
even a beaver, and also three divers swimming under the ice.
- [Narrator] When Märten first started
there wasn't any physics or scientific information
to explain how thin ice skating is possible.
He studied the ice for 10 years every winter
to explain the phenomenon.
- [Märten] I observed three things with the thin ice:
one is that the ice bends, and the thinner it is
the more advanced.
The ice needs to be flexible to support you.
Second, the first crack is a true warning signal,
then I know the ice is thin.
And when it gets even thinner more cracks evoke.
And finally, the ice gives sonorous tone-
beautiful, eerie tone, which immediately tells me
how thick the ice is.
It's called the Coincidence Frequency,
and it can be calculated mathematically.
- [Narrator] Märten has skated
on over 1,800 bodies of water in North America,
Norway and Central and Eastern Europe.
- [Märten] I love skating for the excitement
and challenges it brings.
It's an opportunity for math and nature to come together
and make it understandable for me.
I've been skating most of my life,
and I always look forward to next weekend.