Why The Towers Fell

Though I have never visited, the countless books, movies, tv shows and songs that talk about New York always resonated with me.  9/11 is one of those times in history where you can remember exactly where you were when you first heard the news. 

On September 11th, 2001, the world changed. I was sitting in a classroom at Université Laval in Quebec City in a language lab. My professor stopped my class and spoke in English for the first time.  He said there had been a tragedy and that the Twin Towers in New York City had been hit by two separate airplanes. At first it didn't seem real - how could this happen? How would not one but two planes hit these tall skyscrapers?

Today, over 15 years later the location has undergone remarkable changes as seen here.  Now that years have passed, scientists continue to look for clues and answers as to how and why the buildings collapsed and what, if anything, could have prevented it from happening. Our focus for this lesson will be on the structure itself and what engineers considered when designing the buildings. There is a lot of information about 9/11 with a variety of angles and points of view so for our purposes we will focus on the scientific aspects of structural failure.

We will watch an abbreviated version of a documentary about the Twin Towers called "Why The Towers Fell" discuss how the impact of the airplanes caused their eventual destruction. If this topic of interest for you, I have included a link to the full documentary that originally aired on PBS here and you can watch it at a later time. For now, these are some questions to think about . . .

1. Why do scientists, engineers and city planners think about what may or may not affect structures?  
2. How can people's lives be affected by the efficiency of a structure?

We will watch the short video, Nova - Why the Towers Fell,  then have some time for discussion.