4. Vocabulary/Definitions
buckling: When a column fails by bending at some point in the height of the column, usually towards the midpoint caused by a vertical force.
bundled tube : The design principle that the Sears Tower is built on. The building is basically a collected bunch of tubes, with all the supporting columns of each "tube" located on the perimeter of the tube. This structure is very good at resisting wind loads.
civil engineering : The field of engineering pertaining to non-moving structures such as roads, sewers, towers, buildings and bridges.
deflection : The amount a structure bends or moves from its "at rest" position.
lateral force: A force that impacts a structure horizontally (that is, wind and earthquakes).
tube-style support: Implemented on building such as the World Trade Center, Sears Tower, and many newer structures. The majority of the supporting columns are mover to the perimeter of the tower instead of spread throughout. This allows open expanses of floor space on every floor.

5. Why oh Why?
Engineer design Challenges are fun, but we should also be learning something while we are doing it.
In this challenge we reinforced the Engineer Design Process, focusing on the improve stage.
We can also look at what makes a strong structure
What shapes are most effective
Where is the center of gravity

6. Why doesn’t the Space Needle, a top-heavy skyscraper, ever tip over and fall?
This is reasonable, and there’s precedent for this. After all, the Leaning Tower of Pisa was falling over, and needed significant foundation-work just to keep it upright.

7. Now, when you take something like the Space Needle, it looks like most of the weight is in the top:
And it looks even more significant if you stand at the bottom and look up:

8. Yet, in actuality, the Space Needle is one of the most stable structures ever, and will be one of the last buildings standing in the event of a disastrous earthquake. How is this possible? It’s pretty simple, and requires just one little physics concept: center of gravity. In a human being, your center of gravity is somewhere in your abdomen. The higher your center of gravity is above the floor, the tougher it is to balance. Riding a unicycle, for instance, is particularly difficult: