Monday, January 25, 2016

Cylindrical Structures and Engineering

Mr. Jack had an engineering task for the kiddos this time.  How strong is a cylindrical structure?  He has spent many lessons on the strength of a triangular structure, but now comes the cylinder.

He explained where cylindrical structures are used and how we have cylindrical shaped bones.  He talked about applied force and friction it will cause.  Then he presented the task.

Boys vs Girls was the mission.  He gave each group a large stack of 4"x 4" precut copy paper and rolls of masking tape.  Each group had to design a structure to hold as much weight as possible without collapsing.

Both groups began to roll up single pieces of paper and tape it to maintain the cylinder shape.  The boys divided tasks into rollers, tapers, and designers.  The girls discussed designs as a group, as they created their cylinders.

The boys came up with a very elaborate design that looked maze like.  They were very confident in their structure.  They added extra layers of paper to their preformed columns.  Some columns were twenty or thirty paper pieces thick.

The girls decided to  make single paper rolls but bundled them into groups of four.  The design was very basic.  They had six bundles evenly spaced.

Finally, time was called and the test began.  The boys went first.  They were able to hold 21 books on their structure.  However, the structure was beginning to lean.  When one of the boys sat on top of the books to see if his weight could be held, the structure collapsed.

Next up, the girls.  The boys laughed at the simple design and just knew that it would not work.  Then the girls began to pile on the books.  Their structure held 23 books.  (They had found two more books to use.)  The boys were in awe.  Now, could it hold one of the girls?  The boys doubted it.  However, it did!  The boys had been defeated!  The girls were giddy.

Mr. Jack explained how both designs worked and what had gone wrong with the boys design.  He pointed out that over engineering and looks doesn't always mean its the best.  The boys ended up having 50 columns and some columns contained 20 to 30 sheets of paper.  The girls had 24 columns and used only 24 sheets of paper.  Simple is often the best.

It was a great experiment to see how boys and girls think and approach tasks differently.  Both groups learned more and hopefully remember these lessons next time they are asked to engineer a structure.