Science Assessment ~ Topics ~ Weathering, Erosion, and Deposition ~ Item WE060001 ~ Student Performance

Which of the following is TRUE about how ice could help to change the shape of a valley floor over many millions of years?

The shape of the valley floor can only be changed by ice when the ice breaks rocks as it moves (as in a glacier).
The shape of the valley floor changes when ice breaks rocks as it moves (as in a glacier) and also when water freezes in cracks in the rock of the valley floor.
Ice can break the rock of the valley floor when it moves as a glacier and when it freezes in cracks, but these processes do not help to change the shape of the valley floor.
Neither the movement of ice (as in a glacier) nor water freezing in cracks are strong enough to break the rock of the valley floor, so these processes cannot help to change the shape of a valley floor.

Distribution of responses
Answer Choice		Overall	Grades		Gender		Primary Language
		n = 2521	6–8 n = 1526	9–12 n = 985	Male n = 1222	Female n = 1256	English n = 2222	Other n = 227
A.	The shape of the valley floor can only be changed by ice when the ice breaks rocks as it moves (as in a glacier).	21%	23%	18%	21%	20%	21%	19%
B.	The shape of the valley floor changes when ice breaks rocks as it moves (as in a glacier) and also when water freezes in cracks in the rock of the valley floor.	52%	49%	56%	51%	53%	52%	48%
C.	Ice can break the rock of the valley floor when it moves as a glacier and when it freezes in cracks, but these processes do not help to change the shape of the valley floor.	17%	17%	17%	17%	17%	16%	22%
D.	Neither the movement of ice (as in a glacier) nor water freezing in cracks are strong enough to break the rock of the valley floor, so these processes cannot help to change the shape of a valley floor.	11%	11%	10%	11%	10%	11%	10%

Science Assessment