Building a Catapult

Looking back through past standards and the new NGSS we weren't finding where students were introduced to simple machines, we need them to really have a good grasp on what they are in order for them to complete 4-PS3-4.; Design a simple device using stored energy that will solve a problem.
So we began by examining three different types of simple machines, the lever, inclined plane, and the wheel & axle.  The challenge was for them to build a catapult, which is a type of lever, then classify their lever as a type 1, 2, or 3.
The students worked in teams and  were given a baggie of materials to study for 3 minutes, during this time they were to think of a design that would launch their marshmallow the farthest.  The materials included:
 - one jumbo marshmallow
 - three paper clips
 - a straw
 - two Popsicle sticks
 - a wad of clay
 - a length of string
 - a plastic spoon
 - masking tape

Once they examined their materials they had 25 minutes to construct their design.  It was amazing to hear their conversations and the way they decided on a design and even how to rework their design if it failed. Talk about using good engineering practices!!! Did I mention I love science...! Here are few examples of their work.

We brought back in our measurement standards by then measuring the distance of how far their marshmallows flew- converting it between feet and inches to yards.  We also then had to find the average distance they flew in each trial (we did 3).  

Upon exiting they had to fill out a reflection sheet about how their design worked, what they would change etc.  It was a great learning experience for all!