Make them fully wet and the grains can move without breaking the water so the

that it takes some “oomph” to break apart damp sand grains. Make them fully wet, and the grains can move without “breaking” the water, so the material becomes weak. 1 / 1 pts Question 12 What is accurate about the planet’s climate system? Much more energy is received from the sun than is sent back to space, because highenergy shortwave radiation is received but lowenergy longwave radiation is sent back. Almost the same amount of energy is received from the sun as is sent back to space, but shortwave radiation is received and longwave radiation is sent back to space. Correct! Correct! Much more energy is received from the sun than is sent back to space, because highenergy longwave radiation is received but lowenergy shortwave radiation is sent back.

2/18/2019 RockOn #5: GEOSC 10 Spring 2019, Merged 18/22 Almost the same amount of energy is received from the sun as is sent back to space, but longwave radiation is received and only energy stored by evaporation is sent back to space. Much more energy is sent back to space than is received from the sun, because the planet emits longwave radiation but the sun emits shortwave. Energy in equals energy out, to very close approximation. We actually send back the tiniest bit more, because the Earth makes a little energy radioactively and because we are mining stored energy (fossil fuels) and burning it, and some of that goes to heat the atmosphere but some is lost to space. But, these differences are tiny tiny tiny. (Lie in the sun on the grass on a hot day, and see if you can tell whether the sun or the Earth is supplying the most heat to your skin…). We receive shortwave—visible light—and send back longwave—infrared. 1 / 1 pts Question 13

2/18/2019 RockOn #5: GEOSC 10 Spring 2019, Merged 19/22 In the picture above, when Dr. Alley slices his finger through the sand, he is recreating on a smaller scale what type of geologic process? The action of mass wasting, as soil and rock collapses off of newly steep canyon walls initially carved out by water. Correct! Correct! The action of earthworms burrowing in loose soil. The action of Chuck Norris karate chopping someone. The action of an earthquake tearing apart continents. The action of waves making a beach in Hawaii.

2/18/2019 RockOn #5: GEOSC 10 Spring 2019, Merged 20/22 Despite any passing resemblance, Dr. Alley is not using martialarts techniques to extract money from sand. Instead, he is showing how a river carves a canyon, which then widens as mass wasting occurs on the steep new walls. 1 / 1 pts Question 14 In the photo above, Sam Ascah is standing on sand and gravel in a pothole, where a stream swirls during the short but intense thunderstorms of Zion National Park. And next to that stream, the other picture shows the sandstone and the hangonsoyoudon'tfalloverthecliff chain along the trail. A likely interpretation of these features is: The grooves behind the chain have been cut over decades by motion of the chain as hikers grabbed it, and the potholes were cut by water swirling rocks around during the rare floods over much longer times.