E) The groin of the beach is attached to the pelvis of the beach at the elbow of Cape Cod, making for some strange scientific anatomy. Points Earned: 1.0/1. 0 Correct A
Answer(s): 3. Beaches change size with every storm, but if you average over a few decades, the size of a typical sandy beach is usually controlled by: A) The balance between gain of quartz sand from weathering of granite bluffs just behind the beach, and loss of sand blown away to make sand dunes. B) The balance between removal of sand from the beach by smaller summertime waves, and gain of sand from deep water by bigger wintertime waves. C) The balance between sand loss to deep water, and sand supply from rivers or from coastal erosion. D) The balance between sand loss to the wind, and sand supply from glaciers. E) The balance between sand dug up from below by crabs, and sand taken inland in the shorts of small beach-goers. Points Earned: 1.0/1. 0 Correct Answer(s): C 4. If you watched a sand grain moved by waves on a beach on the U.S. east coast, you would usually see that most of its motion: A) Is to the north. B) Is to the south. C) Is to the north in the winter and to the south in the summer. D) Is from the shore to the sea in the summer, and from the sea to the shore in the winter. E) Is alternately toward and away from the shore, causing little net change. Feedback: A beach sand grain spends most of its time coming in, going out, coming in, going out, and not getting anywhere. A tiny bias exists, such that the in and out will move slightly along the coast, and will cause seasonal changes. Points Earned: 1.0/1. 0 Correct Answer(s): E
5. The above Landsat image from NASA shows Cape Cod, Massachusetts. The short yellow arrow indicates new sand deposits, which have formed over the last decades. The long pink arrow indicates underwater sand deposits. The dotted blue arrow points to the great Outer Beach of the Cape. Based on material presented in this class, what is going on? A) The ocean is eroding the outer beach, but the ocean is also taking sand from the pink- arrowed underwater deposits to add to the yellow-arrowed regions where the Cape is growing. B) The ocean is eroding the blue-arrowed outer beach, and all of that sand is transferred to the yellow-arrowed end, while nothing happens to the pink-arrowed underwater sand, so the Cape as a whole is holding its own. C) The ocean is eroding the blue-arrowed outer beach, and the yellow-arrowed end is growing more slowly, with some sand falling off to the pink-arrowed deposits and then off into deeper water, so the Cape as a whole is shrinking. D) The ocean is “mining” material from the pink-arrowed region, and adding that material to the yellow-arrowed and blue-arrowed places, so the Cape is getting longer as well as wider. E) The yellow and pink arrows actually indicate piles of peripherals lost by wintertime nudists sunbathing on the Cape’s beaches. Feedback: The blue-arrowed Outer Beach is eroding, losing some sand to the yellow-arrowed Monomoy Island—a remarkable birding spot—and some sand to the pink-arrowed underwater
bars, which lose sand to deeper water—the Cape is losing ground. Furthermore, the Cape is
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