I am fascinated with skyscrapers! I opened my lesson today asking my students if any had been on the Chicago Architectual Tour? I explained that one of my favorite experiences in 2014 was a tour with my family on a boat that took us smack dab through the city on the river. I explained that it deepened my appreciation for not only the city, but of how engineers and architects design skyscrapers. I explained that the soil is challenging in Chicago because it basically is a swamp.
I posed the next question: What skyscraper is the tallest?
Students offered up their knowledge....
I told them that every time one is built, another one is being planned to be even taller. How high can we go?
This You Tube Video from SciFi is a great video resource to help them understand. (Have it set up ahead of time to get rid of the ad. I love this resource, but the ads can be a problem.) I told my students that as they watched, I wanted them to note things he said about engineers and about design. I wanted them to know they would need some of this information for the next part of our lesson.
When we were done, I asked them to tell me about what surprised them?
Then, I asked them to jot a question they have about designing skyscrapers down in their notebook.
I gave them about three minutes to write and then drew their attention to the natural forces that have to be considered. I asked about how the wind affects them? I asked them what they thought was the most dangerous natural thing that could harm or destroy a skyscraper.
I explained that they would be using their engineering process skills to design a model skyscraper to withstand a model earth quake.
Materials: A plastic storage container that is about 4 inches deep, sand, gravel, larger small rocks, & potting soil. You can use florist foam oasis to create a bedrock layer or you can use homemade or purchased brown* play dough clay, a Lego set that includes bricks to make skyscrapers, a ruler and a timer.
* in the play dough recipe, you need to color it with 13 drops of red food coloring, 12 drops of yellow, and 6 drops of green per 1.5 cups of flour, 3/4 cup of salt and 1.5 cups of water. You need to figure that you need 1 cups of play dough per model site.
Half of the teams get Site 1 and half get Site 2.
Site 1 has 1" of wet floral oasis foam on the bottom layer and then layer with 1 cup of play dough, 1 cup of sand and 1 cup of soil.
Site 2 has the foam omitted and you layer 1. 5 cups of play dough on the bottom instead. Then layer up a cup of fish gravel, 1.5 cups of sand and then top it with 1.5 cups of soil.
*I like to use a container that isn't clear because then they don't realize they have two different sites. It makes it more interesting. But if all you can get are clear plastic containers, cover the outside with foil or newspaper. Be sure to cover them up tightly if you prepare this the day before so nothing dries out.
I built my own model skyscraper to have on hand if the group seemed nervous about the limitations.
Investigation Goal: Students must design a skyscraper that does not tumble over during a simulated earthquake. Limitations: The skyscraper cannot be more than 2" wide and deep and around 5" tall. There must be evidence of a foundation. Foundations must be built with the 2" rods or narrow 1 dot bricks. They may not extend large brick foundations down into the soil. My students were divided into teams of 4. I reviewed with them The Engineering Design Process, page 4 of this Smart Board File.
I wrote the goal on the white board: Design a skyscraper that will withstand an earthquake on the given site.
I told my students that they needed to use the Lego blocks to create their skyscraper. Firstly, they needed to develop questions about the given site and write them in their notebook using what they learned in their core sample lesson. What did they need to consider? Did they need to take a core sample? This took about 5 minutes.
Then, they were instructed to follow the engineering process I had taught them. I had them state the problem as: This skyscraper must withstand 20 seconds of shaking that imitates seismic activity. After the skyscraper is built, they must test it by shaking the table for 20 seconds and take notes on their observations. They needed to adjust and redesign the building until they could get it to stand in the site for 20 seconds. I then explained their building limitations and used a model Lego skyscraper that I had built.
I gave them a time limit on their design: 15 minutes. Then I gave them an estimated building time limit of 10 minutes. I explained that when building skyscrapers, engineers are always under deadlines that must be met.
I gave them the go ahead to begin!
In teams of three, my students began to design in their notebooks, referring to the engineering practices on the SB. As I roved the classroom, I saw them sketch out basic Lego skyscrapers. I roved the classroom as they completed step two ( we had defined the problem together for step 1). I asked them if there were unknowns they needed to test before they put their building together? One student's hand shot up and he said, "Shouldn't we be doing some sort of test on the soil?" I asked what that test was called and they replied correctly. "Core sample!" I showed them how to do their core sample on the one side, giving them plenty of room for their building. They did the samples and evaluated the soil. They continued to sketch and plan their buildings. I approved skyscrapers one by one and they gathered their Lego blocks and got going. Some had finished in less time than the 15 minute limit. I reminded them of their time limit to build. I guided them to consider design and consider reality so they had awareness of the importance of geotechnical engineering. This connection was really the fun part of the whole thing for me as a teacher!
As soon as a skyscraper was ready to test, I had them place it in their site box on a student desk. I showed them how to shake the table to imitate a tremor. Two students were on each end and the third student timed 20 seconds. They wrote observations in their notebooks and began to revise their skyscrapers for another go around with the earthquake. I roved the classroom, videoing their progress and asking about where it was anchored? I needed to remind them that the first time the, topsoil layer had to be tested. The top layer produced a time of 7.59 seconds for one team.
Soon, all the groups were testing their skyscrapers. The buildings that were in the sandier soil toppled sooner and I could see that those groups were scrambling to get their skyscrapers foundations adjusted. As they progressed to the clay, we started to see success!
As they worked, I looked at the clock and told them that they could work another 10 minutes to succeed at stabilizing their building. As soon as the time was up, we gathered to talk about our observations.
When time was up, all but one team had success. One tower that was a design that was wider at the bottom was the most successful. These students worked well and as they shared, one thing that became clear was that they had communicated well with one another, worked together and understood their core samples well. "We knew we would have to hit the clay before it would hold," one student shared. Another team never did succeed at getting their design perfected and one other team needed to redo their tests because they started at the clay layer. As these misunderstandings surfaced, we talked about what makes a good team. "It's give and take," I said. "Those of you who accomplished your building goals all had good communication skills. Each of you bring something to the table and on an engineering team, it is important that you tap on those ideas from each of your team members. Teamwork is key." I told those who were not happy with their designs or didn't feel successful, could come in at recess and work again.
I explained that part of the engineering process was to redesign the building until it worked. We could understand that many things have to be considered, models tested and redone if necessary.