The Mission
In science class, we were challenged to act like civil engineers and design a tower that could survive a massive earthquake on our classroom shake table!
Our building had to meet these strict rules:
Be at least 30 cm tall.
Only use our limited supply of skewers, and connectors.
Our plan of the tower tower standing tall.
The Science Behind the Build: Elasticity vs. Plasticity
Before we started building, we had to learn how materials respond to forces so we could choose the right ones for our structure:
Elasticity is the ability for an object to stretch and go back to its original form like if you pull a spring to its absolute limit and let go and it goes back to its original form it is Elasticity.
In our building, we used wooden skewers for elasticity because it’s sturdy and an easy material to use for building a strong model.
Plasticity is when a force is put into a shape and can’t go back into its original form. For example, if you stretch a piece of blu tac it can’t go back to its original shape.
In our building, we used hard plastic connectors for plasticity because it holds the wooden skewers in place and makes them sturdy and stay in place. But somehow when we connected it, it did stay in place and that was a big problem. Because some of it were not that connected together.
Our Design & Strategy
When drawing our plan, my group decided to use squares for our frame because we thought it would be way stronger than triangles. Triangles don’t shake that easily because of their shape when as a square at the top it shakes very violently.
Here is how we put our tower together:
- The Base: We used the little plastic connectors to join our base together. We first created a pyramid base then we added on from there to make it reach the minimum 30cm.
- The Dampers/Joints: We used the joints to connect our structure together and in the end our structure had a very unique shape, it had straight skewers and curved skewers.
The Shake Table Test!
It was time for the ultimate test! We placed our tower onto the shake table and held our breath and I was nervous that our one wouldn’t work.
Magnitude 7 Test (Violent Shaking): Our structure was just a bit broken after the earthquake, but in the end some of our structure survived and I think we did pass the shake test.
Testing our structure under extreme shaking!*
Evaluation and Analysis
Our structure kind of survived during the shake table assessment.
Key Observations:
- Strengths: The following design elements were particularly effective in maintaining stability: The heart of our structure was the pyramid in the middle of our structure and our sturdy base.
- Areas for Improvement: Our structure was both elastic and plastic. failure when
- Iterative Design: If given the opportunity to refine our design, I would modify the upper base of our one because it was very loose and did not survive it, I would put more sturdier skewers to enhance the structural integrity.
Join the Conversation
What are your thoughts on our engineering approach? Have you personally experienced an earthquake in New Zealand? We invite you to share your insights or experiences in the comments below.