Riddles of Sand and Ice
Miracle Planet
KEY
An ice age is defined as a time when a semi-permanent layer of snow and ice cover large regions.
1.
Glaciers left behind erratics like the slab of bedrock in Alberta, Canada. What are erratics?
Non-native boulders transported by glaciers
2.
How thick was the glacier over Manhattan 18,000 years ago? 300 feet
3.
Ice was 2.5 miles thick in some areas during the Pleistocene. How many ice ages have occurred
over the last million years? At least 10
4.
Why are glaciologists studying Greenland? They are using it as a model to learn about the ice age
and continental glaciers
5.
There are more than 2,400 trillion tons of ice over Greenland but liquid water is present.
Streams or lakes and rivers flow into the glaciers and under the ice sheet more than
one mile(s) beneath.
6.
How do computers and technology help scientists study the land beneath the glaciers? Allow
scientists to use simulations and satellite images
7.
Give at least three characteristics of Greenland: 1500 X 600 miles; Hollowed out at the center;
Covered by ice and snow; Much of it is below sea level; Lowest spot is more than two miles below sea
level
8.
In Juneau, Alaska scientists are studying glacial movement. What is the surface of a glacier
like? (Give at least two different characteristics) Full of rocks, plants and other debris; Covered with
snow; Has large cracks called crevasses
9.
What are crevasses? Large, deep cracks in the glacier
10.
How are crevasses formed? Can form from water running off and eroding the ice; They can also form
from the ice moving over uneven surfaces
11.
The Inuit people named the mountain peaks sticking out of the glaciers “Nunitaks” which
means: “Lonely Stone”
12.
How do glaciologists study the growth of glaciers? (Hint: layers) Dig holes into the glacier called
“test pits”
13.
Firn is one of the transition materials occurring during the change from snow to glacial ice
14.
What causes the dark bands found within glaciers? Surface of the glacier being covered with dust
in the summer
15.
Ice crystals change with depth in the glacier. How does the crystals’ appearance change as
depth increases? At 50 feet the ice crystals are 1/10 of an inch; At 100 feet, the crystals are bigger due
to the ice pressing down at 3 tons per square foot; The crystal enlarge and align themselves
16.
How does the phenomenon mentioned in question #15 cause glaciers to move? The crystals
polarize and as they flatten out the base of the glacier spreads out
17.
What do the jagged stones embedded in the lowest levels of the glacier do to the bedrock? They
act like a rasp and gouge the bedrock
18.
Which general direction do continental glaciers move? In a general north to south direction
19.
What two changes cause the average global temperatures to drop? The change in the earth’s orbit
around the sun and the change in the inclination or tilt of the earth
20.
What is more influential in the ice age, cooler summers or colder winters? Cool summers