HW 8

20)How does the greenhouse effect work?

Greenhouse gases transmit visible light, allowing it to heat the surface, but then absorb infrared light from Earth, trapping the heat near the surface.

10)Which of the following best describes convection?

It is the process in which warm material expands and rises while cool material contracts and falls.

7)What do we conclude if a planet has few impact craters of any size?

Other geological processes have wiped out craters.

8)In the context of plate tectonics, what is a subduction zone?

a place where a seafloor plate is sliding under a continental plate

5)Greenhouse gases in the atmosphere, such as carbon dioxide and water vapor, make Earth warmer than it would be otherwise because these gases __________.

absorb infrared light emitted by the surface

2)Why is the sky blue (on Earth)?

because molecules scatter blue light more effectively than red light

18)What kind of surface features may result from tectonics?

cliffs mountains valleys volcanoes

13)Which two properties are most important in determining the surface temperature of a planet?

distance from the Sun and atmosphere

9)When we say that a liquid has a high viscosity, we mean that it

flows slowly like honey.

5)Earth's temperature remains fairly steady, which means that Earth must return the same amount of energy to space that it receives from the Sun. In what forms does Earth return most of this energy to space?

infrared light emitted by the surface and atmosphere visible light reflected by clouds visible light reflected by the surface

12)Heat escapes from a planet's surface into space by thermal radiation. Planets radiate almost entirely in the wavelength range of the

infrared.

3)Where is most of the CO2 that has outgassed from Earth's volcanoes?

locked up in rocks

21)The sky is blue because

molecules scatter blue light more effectively than red light.

19)Which of the following gases absorbs ultraviolet light best?

ozone

22)Sunsets are red because

sunlight must pass through more atmosphere then, and the atmosphere scatters even more light at bluer wavelengths, transmitting mostly red light.

15)When we see a region of a planet that is not as heavily cratered as other regions, we conclude that

the surface in the region is younger than the surface in more heavily cratered regions.

5)The energy that warms Earth's surface comes primarily in the form of __________.

visible light from the Sun

1)Which of the following is a strong greenhouse gas?

water vapor

11)What are the circumstances under which convection can occur in a substance?

when the substance is strongly heated from underneath