Saturday, March 5, 2016


This week, it was Teacher Nalani's turn to lead the science discussion about FORCE.  
A tug of war is a great example of the pulling force.
Gravity is a big force, pulling us down to the earth's surface. 

The discussion turned toward the structural engineer's challenge to build a bridge, using  push and pull forces to ensure its strength.   
We talked about the different types of bridges: the arch bridge, the truss bridge, and the suspension bridge, and how they each use force to ensure its strength and stability.

We learned a brief history of the man who was hired to build the beautiful Golden Gate bridge. He had the challenge of building a bridge over a mile long, over a deep channel and still allow for large boats to travel underneath.   Suspension bridge to the rescue!  (Suspension = think suspenders)

Then, it was our turn to put on our structural engineer skills to work.  The students were split into groups of two and given two sheets of copier paper to fold, cut, and manipulate into a 3" wide x 6" long paper "bridge".  We used pennies to test the bridge's strength.

Sometimes, a "failure" is a valuable tool when experimenting! When the bridge collapsed under the weight of the pennies, we could visually see where the bridge needed some adjusting.   A fold or two of the paper, made the difference between a bridge that could hold 50 pennies, and a bridge that could hold 100 pennies.

Scientific process success!  After many tries- our classroom full of scientists figured out that the strongest bridge had "truss" folds on the sides and down the middle.
Congratulations to Aiyanna Ellis.  She had the "winning" bridge that held 182 pennies!!