Earth Science

The outermost layer of the earth is about 3 to 30 miles thick. It is called the

• mantle
• crust
• outer core
• inner core

The second layer of the earth goes down 1800 miles. It is called the

• crust
• outer core
• inner core
• mantle

Oldham found the earth's core when he saw that seismic waves from ___________ didn't go straight through the center of the earth.

• tidal waves
• earthquakes
• mountains
• ocean floors

Lehmann discovered that the earth actually had two ________.

• mantles
• layers of crust
• cores
• atmospheres

The inner core is made of iron that's almost as hot as the sun - why doesn't it melt?

• Iron doesn't melt
• That's not really very warm
• Pressure is super high
• Oceans cool it

The moon is now much cooler that the earth. Why?

• Earth is bigger so cools slower
• Moon gets no sunlight
• Moon is actually warmer
• Earth has water on it

Wegener wondered how fossil and living creatures

• ended up on different continents
• got frozen in ice
• died
• created earthquake waves

Wegener noticed that the edges of some continents

• were exactly the same
• overlapped each other
• were covered with mountains
• fit together like puzzle pieces

Scientists rejected Wegener's idea of Continental Drift because

• no fossil evidence for it
• continent shapes didn't fit
• didn't trust him
• no known mechanism 

Harry Hess found that the ocean floor was _____________ the farther it was from the mid-ocean ridge.

• older
• younger
• backwards
• opposite