(Some of the answers may come from the vocabulary list.)
- The formation of a huge glacier begins with a single, small _____________?
- What types of summer temperatures need to occur for a glacier to form?
- How does over-lying weight affect the snow?
- What is wetted snow that has survived one summer without being transformed into glacier ice?
- How long does it take for firn to form?
- When does firn become glacial ice?
- What is the line that separates bare ice from the snow at the end of the ablation season?
- What is the difference between a perennial snow patch and a glacier?
- What causes a glacier to move downhill?
What would Alaska look like if all of the glaciers melted?
Exercise: Circle the Facts
Circle all the statements that are true about each word given (more than one statement may be true).
A. is wet snow that has survived one summer without being completely turned into ice
B. are plants your cat likes to eat
C. takes a year to form
D. becomes glacier ice when it is more compressed
E. is what you call snow when it’s freshly fallen on the glacier
A. change to firn
B. is the name of your pet rattlesnake
C. is the first step in the formation of glacier ice
D. is a six-sided crystal
E. can’t form glacier ice
Snow on a glacier:
A. is only used for snowball fights
B. builds up on a glacier in the accumulation zone
C. causes the grains of snow beneath it to enlarge
D. will melt instantly because the glacier is so hot
E. will feed all the ice worms
Project: Firn Structure
- snow or ice shavings from ice cubes or freezer frost
- very cold water (close to freezing)
- a small container that you can seal
- a larger container
- Mix the ice in your small container with enough water to make slushy snow. Seal the container. Next, make an ice bath with a mixture of half water and half ice and sink your sealed container into the bath. If you’re able, put the whole experiment into a refrigerator.
- After 24 hours, remove the sealed container and drain all the water. Use some tissue to pat dry the snow.
- Reseal the container and put it back in the ice bath for a few hours.
- When this is done, pull the sealed container out and look at the remaining ice with a magnifying lens of at least 5x magnification. You should see clusters of rounded ice particles, very similar to the structure of firn.
(Courtesy of Glaciers of North America, By S. Ferguson)