Junk drawer science

"Children love challenges, especially ones that involve hands-on experimentation and friendly competition. Can they build a bridge using only pasta and glue, one that a toy car can drive both under and over, and is sturdy enough to carry a considerable weight? Can they construct a "roller coaster" from recycled cardboard tubes in which the marble "car" jumps a track to land safely at its final destination? And can they create a device to safely catch...