The History of the Earth: Supplemental Guide 3B | The Earth Inside-Out, Part II 65

Extensions 20 minutes

Riddles for Core Content 10 minutes

• Show students Image Card 1 (Heat), and remind them that they
  learned about heat, the fi rst of the three forces that change the
  earth.


• Show students Image Card 2 (Pressure), and remind them that
  they learned about pressure, the second of the three forces that
  change the earth.


• Show students Image Card 3 (Time), and remind them that they
  learned about time, the third of three forces that change the
  earth.


• Show students Image Card 4 (Earth’s Layers), and ask them
  to name the layers of the earth. [From outside to inside: crust,
  mantle, outer core, inner core.]


• Show students Image Card 5 (Volcano), and ask them to tell
  you what they see in the image. [Volcanoes occur when heat
  and pressure build over time until magma erupts and then lava
  or fl owing, liquid rock covers the ground until it cools into rock
  again.]


• Tell students that you are also going to say a riddle about each
  of these Image Cards. Tell them to listen carefully to see if
  they can guess the correct answer. Ask students the following
  riddles:

1. Some people measure me with a clock, but I cannot be seen.
   What am I? (time)


2. I shoot gooey rock or magma. When it hits the earth’s crust, it
   cools and we call it lava. What am I? (volcano)


3. I have layers, like a bed, but I am shaped like a ball. People
   and animals live on my crust. What am I? (Earth)

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