Kids will create a paper bridge between two paper cups, attempting to balance a third cup on the bridge. The structural differences and strength of an unaltered single piece of paper will be compared to that of an accordion-folded bridge to discuss building technique and application. Experiment details can be found here.
Source: Forbes, E., Hale, J. and Christianson, C. Creative Kids: Simple Science Fun. California: Teacher Created Resources, 2010. eBook.
Shoot marshmallows from a catapult made with wire hangars, rubber bands, and plastic spoons. Learn more here.
Using raw eggs, children will explore the strength of an emptied half eggshell and discuss the effect shape/geometry have on strength of construction.
Experiment details can be found at Science Fair Adventures here.
Create a hovercraft with a baloon and CD and discuss the scientific principles that support its movement.
Create cars from limited supplies and race them-powered by blowing on them.
Paper Cup Stand
Participants will create a platform of paper cups and cardboard to support their weight, leading to a discussion of weight distribution.
Make a pencil balance on its tip using wire and clothespins.
This is a quick easy rocket activity. You supply the launchers. The kids need only paper and tape to make the rockets. There are multiple versions. For safety sake, you may wish to improvise a launching stand for those that use handheld launchers. See three versions here, here, and here. KIDS LOVE THESE!!!
Using a milk carton, tinkertoys, and a variety of cardboard blades, children create miniature windmills. They can change the size, shape, number, and angle of the blades to see which configuration lifts the most weight, and in the process learn the principles of wind power generation.
See full activity here.