How Earth formed and separated into layers

Grade 9 Science Worksheet - Building Confidence

Circle the best answer.

1. 1.

   What had to happen before Earth's iron could sink to the center, by Bo's reading?

   • Earth had to be hot enough to partly melt
   • Nothing; the layers were there from the start
   • Earth had to cool and freeze solid
   • The iron had to float to the top

2. Read this first

   Table, Earth's layers (USGS), with columns Layer, Thickness, State

   Crust, about 5 km (oceans) to 30 km (continents), solid, brittle; mantle, about 2,900 km, hot, semi-solid rock; outer core, about 2,200 km, liquid iron-nickel; inner core, about 1,250 km, solid iron-nickel.

3. 2.

   Which material ended up at Earth's center, by Kira's reading (USGS)?

   • Light crust rock
   • A giant magnet that makes the magnetic field
   • Iron and nickel
   • Water
4. 3.

   Which layer is liquid, by Jun's reading (USGS)?

   • The inner core
   • The outer core
   • Each layer
   • The crust
5. 4.

   About how thick is the crust under the oceans, by Luz's reading (USGS)?

   • About 5 km
   • About 2,900 km
   • About 500 km
   • About 1,250 km
6. 5.

   What creates Earth's magnetic field, by Milo's reading (USGS)?

   • A giant bar magnet in the crust
   • The spinning liquid outer core
   • The Moon
   • The solid crust's iron rocks

7. Table, Earth's layers (USGS), with columns Layer, Thickness, State

   Crust, about 5 km (oceans) to 30 km (continents), solid, brittle; mantle, about 2,900 km, hot, semi-solid rock; outer core, about 2,200 km, liquid iron-nickel; inner core, about 1,250 km, solid iron-nickel.

8. 6.

   Which order runs from least dense to most dense, by Noah's reading?

   • Crust, mantle, core
   • Mantle, crust, core
   • They are equally dense
   • Core, mantle, crust
9. 7.

   USGS says the core is nearly twice as dense as the mantle. Why, by Pia's reading?

   • It is made of lighter rock
   • It is made of metal, iron and nickel, not stone
   • It is full of water
   • It is made of gas
10. 8.

    Timeline ruler in billions of years. About how old is Earth, by Tala's reading (USGS)?

    • About 4.54 million years
    • About 6,000 years
    • About 4.54 billion years
    • About 13.8 billion years, the universe's age
11. 9.

    Which formed first: the solar system's oldest solids or Earth's layers, by Zee's reading?

    • The oldest solids, then Earth and its layers
    • Earth formed long before the Sun
    • They formed in the same instant
    • Earth's layers came first
12. 10.

    How does a boiled egg compare with Earth's layers, by Esme's reading (USGS)?

    • Shell like the core, yolk like the crust
    • Shell like the crust, white like the mantle, yolk like the core
    • The shell is as thick as the white
    • The yolk is liquid throughout, like the inner core