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Glaciers: rivers of ice

Science · Polar Regions · ages 9-11

Name ______________________ Date ____________

Where are Earth's two ice sheets?
- Greenland and Antarctica
- Iceland and northern Norway
- The Arctic Ocean and Alaska
How does snow turn into glacier ice?
- It becomes glacier ice when all the snow melts away each summer.
- It builds up, and its weight presses older snow into dense ice.
- It becomes glacier ice when strong winds freeze falling rain.
Ice cores contain trapped air bubbles that show what Earth's air was like long ago.
Circle one: True False
Use rounded estimates of 7 metres for Greenland and 58 metres for Antarctica. If both ice sheets completely melted, about how many metres would global sea level rise?
Answer: ______________
A glacier wears away a mountain valley over thousands of years. What shape does this often produce?
- A narrow valley with a V-shaped cross-section
- A broad valley with a U-shaped cross-section
- A valley with perfectly flat walls and no floor
Why do scientists drill deep ice cores instead of studying only an ice sheet's surface?
- To reach older ice and its trapped samples of air
- To find layers where no snow has ever fallen on the ice
- To prove that surface ice contains no traces of air
An ice sample is 800,000 years old. Another sample is half that age. How many years old is the second sample?
Answer: ______________
Mia says a glacier moves too slowly to change the land. Which explanation checks her claim?
- Glacier ice melts before it can carry any rock or soil.
- Glacier ice stays still while rivers carve all valleys.
- Slow ice still wears away rock and leaves moraines.

Answer key

For grown-ups. Fold this page away before handing over the rest.

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Greenland and Antarctica · Earth's two ice sheets cover large areas of land in Greenland and Antarctica.
It builds up, and its weight presses older snow into dense ice. · Snow survives melting and is buried by more snow. The growing weight presses the older snow into dense ice.
True · Bubbles sealed inside glacier ice preserve samples of past air. Scientists can measure the gases in them.
65 · Add the rounded estimates: 7 + 58 = 65 metres. Complete melting is a condition, not a forecast for a named year.
A broad valley with a U-shaped cross-section · Moving ice and the rocks it carries wear away the valley floor and sides, often producing a broad U-shaped valley.
To reach older ice and its trapped samples of air · Older layers usually lie beneath newer layers. Drilling can reach older ice and the air preserved inside it.
400000 · Half means divide by 2. 800,000 divided by 2 is 400,000 years.
Slow ice still wears away rock and leaves moraines. · Slow glacier movement can wear away rock over many years. Glaciers also carry rock and soil and deposit moraines.