This afternoon we had a design challenge to create a cotton ball catapult.  Here is the website that set up the challenge.
http://pbskids.org/zoom/activities/sci/cottonballcatapult.html
Then we looked at some movies of real catapults in action.  We had 20 minutes to build and the objective was to have the cotton ball go the longest distance.  Here are some pictures of their catapults.

The team that one was the only team that used the ruler horizontally.  We discuss why they thought this made the difference.  Congratulations to Ellorie and Elijah.  They won with 304cm.  Wow!!!!