Just tray to keep your drinks from spilling
http://pbskids.org/zoom/activities/sci/steadytray.html
The trick to what sticks
http://pbskids.org/zoom/activities/sci/stickometer.html
Make a raft that will float your boat, and some potatoes....
http://pbskids.org/zoom/activities/sci/survivalraft.html
Look Ma, no hands! Invent a Tennis Ball Lifting Contraption.
http://pbskids.org/zoom/activities/sci/tennisballlift.html
Hydro-neers wanted. Invent a filter to clean dirty water.
http://pbskids.org/zoom/activities/sci/waterfilter.html
Filter out how to survive on a deserted island
http://pbskids.org/zoom/activities/sci/waterfilterpartii.html
Control the back and forth of a super ball
http://pbskids.org/zoom/activities/sci/youcantgettherefromh.html
This interesting experiment shows you how to build a simple hovercraft that can lift several adults!
http://amasci.com/amateur/hovercft.html
The purpose of this experiment was to determine whether suspension bridges or cable -stayed bridges would support the most mass.
http://www.selah.k12.wa.us/SOAR/SciProj2000/MeganC.html
Ever wonder why igloos are dome shaped and not square? Ever been amazed at how a suspension bridge can hold the weight of hundreds of passing cars with little or no apparent support underneath it?
http://www.spartechsoftware.com/reeko/Experiments/ExpEggShellArches.htm