Review - Earth and the Moon

Which part of the Earth has the lowest density?

• oceanic crust

• continental crust

• mantle

• core

• Whitehouse, TX

If no one has ever visited the core of the Earth, how do we know that it is made of metals?

• core material seeps up through volcanoes in the crust

• circulating liquid metals in the core set up a large (measurable) magnetic field

• spectroscopy allows us to tell what the core is made of by analyzing the light we receive

• the amount of radioactivity shows metals must be present; only metals are radioactive

• you can't fool me; there is NO evidence that the Earth's core has metals

Earthquake producing faults are most likely to be found

• in smooth continental desert areas

• in the southern hemisphere of the Earth, where there is more water

• where the Earth's magnetic field touches the planet's surface

• on the boundaries of continental plates, where they meet other plates

• you can't fool me, such faults are equally likely anywhere on the Earth's crust

According to the theory of plate tectonics,

• the continents are moving but the ocean floor is not, leading to great friction

• the rubbing of the waters of the Earth across its crust is speeding up its rotation

• the liquid metal inside the Earth is developing plates of solid metallic material, which contribute to the Earth's magnetic field

• earthquakes are caused by huge waves that come up from inside the molten core of the Earth

• slow motions within the mantle of the Earth move large sections of the crust around

In which region of the Earth's atmosphere are most clouds located?

• the ionosphere

• the stratosphere

• the troposphere

• the ozone layer

• the mesosphere

Which of the following points about our planet's atmosphere is FALSE?

• it is slowly leaking atoms into space from its outermost regions

• its mass is a substantial part of the mass of the Earth

• warm air rises and cool air descends within it, setting up circulating currents `

• it is made mostly of nitrogen

• one of its layers helps keep much of the ultraviolet radiation from space from reaching the surface

In terms of numbers, the most common life-forms on Earth are

• humans

• fish

• microscopic creatures, too small to see with our eyes

• birds

• insects

The average temperature on planet Earth is higher than you would expect just from the heating of sunlight alone. What is the explanation for this?

• solid material hitting the Earth from space heats it up

• carbon dioxide (and other gases) in the atmosphere causes a greenhouse effect

• the rubbing of the continental plates warms up the Earth's surface

• the heat given off by living things makes our planet warmer

• we have no explanation for this higher temperature and that has scientists worried

Which of the following is NOT evidence that objects from space collide with the Earth?

• the devastation that happened in 1908 near the Tunguska river in Siberia

• Meteor Crater in Arizona

• the crater at the top of the Mount St. Helens volcano

• the Chicxulub crater buried near Mexico

• you can't fool me; all the above are the results of cosmic impacts

The Moon is heavily cratered, but the Earth which "lives next door" is NOT. Why?

• the magnetism of the Moon is more likely to attract metallic objects to hit it

• all objects from space (no matter what their size) burn up in the Earth's atmosphere

• the craters on the Moon are the result of active volcanoes; the Earth has few volcanoes compared to the Moon

• the active geology and weather on Earth destroy traces of impacts over millions of years

• the Earth is heavily cratered, but all the craters are under the ocean