Ice can be the bane of your existence in winter, turning streets and sidewalks into slippery deathtraps. But when conditions are just right, ice can
create all sorts of weird phenomena. It’s delicate enough to form beautiful flowers
of frost, but powerful enough to fuel earthquakes. If you’re in the Northern Hemisphere, keep
your eyes peeled in the next couple of months, and maybe you’ll get lucky enough – or
unlucky enough – to spot one of the weird, icy wonders on this list. Let’s start with ice spikes. You’ve probably seen tons of icicles – but
have you ever seen one that formed upside down? Ice spikes seem to defy gravity, growing upward
from an icy surface. Sometimes they’re outdoors, like in a bird
bath, but you’re most likely to see them on ice cubes in your freezer. They may look impossible, but they’re a
result of the quirky way that water freezes. Most liquids freeze from the bottom up – the
cooler molecules are more densely packed, and sink as they start forming a solid. But water is weird. It actually becomes less dense and expands as it freezes, because of the way that water molecules arrange themselves in a crystalline structure and form hydrogen bonds. That’s why ice floats in your glass, and
why a pool of water freezes from the top down. When a crust of ice forms, the remaining liquid
water doesn’t really have room to expand as it transitions into a solid state. And sometimes, like in an ice cube tray, it
finds another way to expand. If there’s a tiny gap in the surface ice,
the water underneath can be forced up through it and make a tiny frozen spike. Misty, gloomy fog appears when a cloud of
water droplets forms at ground level. But when the temperature plummets, you might experience a little something called freezing fog. Tiny liquid water droplets suspended in the
air don’t necessarily freeze at 0 degrees Celsius. For ice crystals to form easily, the water
molecules need a bit of something solid that they can glom onto to get aligned and start
crystallizing, which is called nucleation. Without that, water droplets can become supercooled,
staying a liquid below 0 degrees Celsius. But as soon as they touch a solid surface
– BOOM. They instantly freeze. So freezing fog can coat all kinds of things
in a layer of ice. It can be beautiful, making trees and grass
appear to glitter. But – as you might guess – it can also
make for some dangerous driving. That’s why, if you hear the words “freezing
fog” in your forecast, it might be best to plan on a cozy night in. If you hear a loud boom that rattles your
windows on a very, very cold night, don’t be so quick to blame supersonic aircrafts
or aliens. You might have just heard the sound of a frost
quake, also known as a cryoseism. When changing weather causes the temperature
to drop fast enough, water that’s seeped into the soil can freeze rapidly and expand,
causing a miniature explosion underground. The shifting, cracking earth is loud enough
that it reminds some people of sonic booms that planes produce when they break the sound
barrier. Frost quakes are pretty rare outside the polar regions, but they’re not totally unheard of. The winter of 2014 was cold enough to cause
quakes across the upper midwest United States, producing booms loud enough to wake people
up at night. In 2003, a frost quake in Maine even caused
a 20-meter crack to open up in someone’s basement floor. Despite their power, though, these quakes
are usually pretty localized. Seismographs often don’t pick them up, and
people just a mile or two away might not even notice them at all. To see a frost flower on land, head to the
woods the morning after the first hard freeze of fall. These fragile petals and curlicues of ice
form when plant stems rupture in freezing weather, letting the moisture inside ooze
out and freeze when it hits the cold air. Some plants are more likely to form frost
flowers than others, and several different plant species actually share the common name
“frostweed” because of it. One thing all these plants have in common
is that they’re all perennials, which means they have a root system that lives through
the winter. As water seeps out of the split stem tissue,
more is drawn up from the roots thanks to capillary action, the same force that lets
a sponge or paper towel soak up a spill. Water molecules tend to stick each other – which
is called cohesion – and to surfaces around them – or adhesion. So they follow each other up the tiny channels
inside the plant tissues, providing enough moisture to create these exquisite ribbons. But you’ll need good timing to see these
icy blossoms in action. Frost flowers are as short-lived as they are
beautiful, melting as soon as the sunlight touches them. The term frost flower can also refer to flower-like
formations that appear on new, thin sea ice. Because that’s not confusing at all. It’s hard to get close enough to study them,
because they form on such delicate ice. For a long time, we assumed they were formed
by freezing fog depositing ice crystals on the salty ocean surface. But the problem with that theory was that
these frost flowers mostly formed when the air was dry. It turns out that when the air is cold enough,
water sublimates directly into vapor from the solid surface of the ice, skipping the
liquid stage altogether. When this water vapor touches chunks of ice
again, it refreezes thanks to nucleation, and can form flower-like structures. These delicate structures have an unusual
characteristic for ice: they’re salty. Really salty. As salt is pushed out of the sea ice forming
below, the frost flowers wick it up into their crystals, becoming up to three times as salty
as the ocean itself. When scientists from the University of Washington
carefully collected and melted one of these salty sea ice flowers, they found that it
contained less than two milliliters of water – but about one million bacteria. It’s such a cold, salty environment, that
this is a major surprise. And researchers hope that frost flower bacteria
may eventually give us clues about how microbes might survive in other extreme places – even
outer space. On rivers around the world, a strange sight
might appear in winter: perfectly round circles of ice, rotating slowly in the current. These ice discs have been known to reach up
to 100 meters across and last for months. In recent years, they’ve been seen in Canada,
the US, and the UK. But they’re pretty rare, and there are multiple
theories on how they form. One main idea is that they form when ice freezes in a still patch in the middle of a swirling eddy. But a 2016 study also showed that ice discs
will even start to spin under their own power, with no help from moving currents around them. Scientists froze discs of ice in a Petri dish,
and then floated them on the still surface of a water bath. And as the icy discs melted, they became a
cold liquid water, and began to rotate. That’s because the cold water was more dense
than the other water surrounding it, so it started to sink and created a vortex, spinning
the disc on the surface. Abraham Lake, a man-made lake at the base
of the Canadian Rockies, is famous for photogenic bubbles that form in the ice every winter. But be careful – these bubbles can explode. Bacteria living on the bottom of the lake
decompose the dead organic matter down there for energy, and release methane gas that gets
trapped as bubbles in the freezing water. If you poke a hole through the ice, you can
light these bubbles on fire, and scientists have done just that to prove that they really
do contain methane. Methane is a powerful greenhouse gas, seeping
out naturally from wetland habitats around the world. You can find methane bubbles in other lakes
in cold places, but Abraham Lake has a higher concentration of them because it’s man-made. The dam that captures its water also traps
a lot of plant debris that would otherwise be washed away, providing lots of yummy junk
for bacteria to decompose. Thanks to these icy bubbles, Abraham Lake
has become a popular tourist destination, with photographers seeking that sweet Instagram
shot of what are basically bacteria farts. So, hey, road trip anyone? Tsunamis are known for their power, sweeping
away beachfront buildings, and you might have seen some grainy cell phone videos of slow-motion
ice tsunamis doing the same thing. The technical term for this phenomenon is
ice shoves, but if you’ve ever seen one of those walls of ice marching ashore from
a lake on a cold winter day, you’ll see why they remind people of their liquid cousins. In 2013, ice shoves got up to 9 meters high
and damaged homes in Minnesota and Montana, grinding up the lakeshores with a crackling
sound. In Minnesota, the wall of ice made it almost
25 meters inland and stretched along 4 kilometers of shoreline. Videos and photos of the 2013 ice shoves look
surreal, but they actually have a simple explanation. Chunks of ice form on the surface of the lake,
and as strong winds push them towards land, they break up into smaller fragments and pick
up even more ice along the way. So ice shoves are literally just ice being
shoved along, sometimes right onto land. Even though they’ve been known to cause
some nasty damage, at least there’s plenty of time to evacuate before an ice tsunami
hits. Forget outrunning them – these menaces can
easily be out-walked. Even if you never experience a frost quake
or stumble across a frost flower, it’s safe to say that ice is pretty amazing. If it didn’t float on top of liquid water,
aquatic life probably couldn’t exist at all. Fish and other organisms, especially the bottom-dwellers, wouldn’t have anywhere to escape. So it’s no fun to drive on, and we might
get a little too much of it here in the Montana winters, but we shouldn’t take the
power and beauty of water ice for granted. Thanks for watching this episode of SciShow, which was brought to you by our patrons on Patreon. If you want to help support this show, just
go to patreon.com/scishow. And don’t forget to go to youtube.com/scishow and subscribe!
http://imgur.com/a/QB8LW
Ice Discs at Minneopa Falls (Mankato MN)