"Defining Gravity" Crash Course Kids
"Everything Revolves Around You" Crash Course Kids
"Down to Earth" Crash Course Kids
"Our World: Gravity in Space" NASA
*"Physics/Gravity Quiz" ducksters.com
"Your weight on other planets." Exploratorium Edu
"Feather Hammer Drop on Moon" You Tube
"Gravity and Orbits" phet.colorado.edu
"Gravity Challenge" Science Net Links