Skeletons in the Sky: teacher key

How Buildings Stand Up, grade 7 edition, written for 7th grade. Tall buildings stand on steel skeletons, deep foundations and clever ideas about wind. See how engineers solved each problem, from Roman arches to the tube towers of today.

Read the book. Print this page for the key.

Questions and answers

1. Why can a steel-frame building have many windows?
   • The frame carries the weight, not the outer wall (answer)
   • Glass is stronger than stone
   • Windows hold up the roof
2. What did Elisha Otis's safety brake do?
   • Made the elevator move faster
   • Stopped the platform if the rope broke (answer)
   • Cut the rope on purpose
3. What is thrust in an arch?
   • A downward weight
   • A heat from the sun
   • A sideways push that must be resisted (answer)
4. Why did Fazlur Khan move the strong parts to the outside walls?
   • So the building acts like a stiff hollow tube against wind (answer)
   • So the building looks older
   • So there are fewer windows
5. In the word 'damper' as used about Taipei 101, what does a damper do?
   • Adds weight to the base
   • Turns the swaying motion into heat (answer)
   • Lets wind in

Words

• foundation: ground base
• thrust: sideways push
• skyscraper: very tall building
• damper: motion calmer