Ephemeral Yet Powerful (02:30)
Dr. Gabrielle Walker sets out to discover the secrets hidden deep within ice. She will reveal how its power to preserve our past and inform our future lies deep within the ice crystal.
Gabrielle Walker goes to southern Norway to visit the largest glacier in continental Europe. Nigardsbreen is the name of one arm of the glacier. Walker wants to find out what makes glaciers one of the most powerful forces in nature.
Colorful Ice (01:27)
The glacier displays a full range of color from white to dark blue. At the surface, jagged crystals scatter sunlight so it looks white. But pure ice crystals absorb red light. As sunlight travels deeper into the ice, only blue light is reflected back.
A Moving Sculpture (02:00)
Although glacial ice is a solid, it flows like a river, driven by its weight. It is built up from layer upon layer of snow; fresh snowfall keeps it flowing downhill. Progress is slow, but time-lapse photography reveals it moving 275 meters per year.
Inside a Crevasse (02:24)
As the glacier moves, the brittle part on top breaks open. Meltwater can gather in crevasses and start hollowing its way down toward the bedrock. At the bottom of a crevasse, ice meets ground. Melting water helps the glacier slide. The glacier is dynamic.
A Rare Property of Ice (01:50)
The walls of the glacier are a glittering mass of ice crystals, which have an unusual property: they float in water. This makes ice special, giving it the power to transform the world. The secret lies in the curious way water turns from liquid to solid ice.
Why Ice Floats (03:03)
Ice is a crystal of carefully arranged water molecules. The way the ice crystal forms is the key to why it floats. As water cools, the bonds firm up and hold its molecules far apart, making it lighter and less dense than water. This is rare in nature.
Why Ice's Properties Matter (01:50)
If ice didn't float, oceans would freeze from the bottom up, and life as we know it might never have evolved. And we wouldn't be able to skate! English style skating combines Victorian elegance and understatement with a high level of skill.
The Little Ice Age (01:17)
The English style of skating dates back to the 1600s, while Britain was experiencing the Little Ice Age. From the 13th century to the mid-19th century British winters were two degrees cooler. The Thames regularly froze in winter.
Why Ice is Slippery (03:26)
Slipperiness is rare for a solid. In a classic experiment, a weighted wire works its way through a block of ice. Behind the wire, the ice seals up again. Compressing ice pushes it back toward its molten state. Skates melt ice's top layer.
How Ice Can Do the Impossible (01:37)
Its ability to swallow up another solid shows how peculiar ice is. In Norway, at the foot of Nigardsbreen glacier, we hear local stories of how glaciers can engulf very large things, from a farm to an airplane.
Rocks are the Teeth of the Glacier (02:36)
Ice is too fragile to leave any mark on solid rock. It carves out the valley by picking up rocks that scrape away at the land beneath as it moves. It grinds rock into dust so fine it remains suspended in the water of the lake, giving it its color.
Ice in Space (02:00)
Some moons of Jupiter and Saturn are covered in ice, which may be protecting oceans of liquid water. A photo of Jupiter's moon Europa, taken by the Galileo spacecraft, indicates liquid underneath. If confirmed, it will be an amazing discovery.
Amazing Discovery (01:56)
The unmanned probe Cassini revealed water vapor above the surface of Saturn's ice-covered moon, Enceladus, something never seen before in the solar system. Scientists are designing smaller probes to look for evidence of life there.
Life in Icy Environments (01:58)
Strange creatures live under the sea ice at the edge of Antarctica. A scientist explains that the fish that live here can survive in such cold water because they manufacture proteins that act as antifreeze, preventing their organs from freezing.
Unique Ecosystem Revolves Around Ice (02:16)
A scientist explains why the low temperature of the Antarctic sea enables creatures to grow very large. The ice has kept the water temperature low and constant for 25 million years. Studying them, we can learn how icy environments support life.
Arctic Exploration (01:24)
While Antarctica lies on mountainous bedrock, the Arctic is a treacherous ocean of floating sea ice. For hundreds of years sailors searched for a trade route through these waters--the elusive Northwest Passage. We'll learn the story of one expedition.
Sir John Franklin's 1845 Arctic Expedition (02:07)
At the Scott Polar Research Institute are daguerreotypes of the expedition's experienced officers. 133 men set sail from Kent in two sturdy ships, expecting to sail from the Atlantic to the Pacific and return within three years.
A Victorian Mystery (01:36)
The ships of the Franklin Expedition had state of the art equipment, but they disappeared in the Arctic. Rescue missions found no survivors. In 1858 a message was discovered on an island. Both ships had been abandoned in the ice. But why?
Lead Poisoning (03:01)
In 1986 scientists exhumed bodies from the Franklin Expedition that had been buried on Beechey Island. They found the men had toxic levels of lead in their bodies. The lead may have come from the piping in the ship's new water system.
Preserving Past Atmospheres (02:31)
Scientists drill into the Antarctic ice sheet to discover the past. Ice cores preserve ancient air, helping us to understand climate. A scientist shows air bubbles trapped in pieces of ice core ranging from 1000 to 80,000 years old.
Climate Change (01:34)
The chemistry of ice crystals in ice cores reveal the temperature when they originally formed, showing how climate has changed throughout history. The ice core record shows a strong relationship between temperature and CO2.
The Enigma of Ice (01:11)
Ice seems full of contradictions. A solid can pass through without a trace. It can shatter rock and sculpt our planet. In space it may conceal life forms. It can last millions of years or just melt in an instant. That's the secret of its power.
Credits: The Secret Life of Ice (00:31)
Credits: The Secret Life of Ice
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