Why Towers Don't Topple: teacher key

How Buildings Stand Up, grade 4 edition, written for 4th grade. Walls that used to hold buildings up gave way to steel frames. See how frames, tubes and triangles let towers reach the sky.

Read the book. Print this page for the key.

Questions and answers

1. What did steel frames let outer walls have?
   • Thicker stone
   • More windows (answer)
   • Fewer floors
2. What makes concrete strong when it is pulled?
   • Steel bars inside it (answer)
   • Extra water
   • A coat of paint
3. What does a deep foundation do?
   • Stops the wind
   • Holds the elevators
   • Carries the load to stronger layers (answer)
4. Which way does the pendulum in Taipei 101 swing?
   • With the tower
   • It stays still
   • Opposite the tower (answer)
5. Why did the first skyscraper need both steel frames and elevators?
   • The frame held it up and the elevator let people reach high floors (answer)
   • Steel made the elevator work
   • Elevators made the walls thick

Words

• masonry: stone or brick
• pendulum: swinging weight
• foundation: building's base
• truss: triangle frame
• tension: stretching force