Set a piece of foam core board or cardboard on a flat surface. Line one cardboard tube or paper towel roll with bubble wrap by rolling up a piece of bubble wrap and attaching it to the inside of the tube with a few pieces of double-sided tape. Ensure that the resulting diameter is still large enough to allow a marble, small rubber bouncy ball, small ball of clay and gumball to pass through.
Line another two to three cardboard tubes or paper towel rolls with fabric of your choice; choose different fabrics with varying textures like cotton, flannel, velvet and other materials in varying levels of thickness and softness. Glue the fabric to the inside of the tube.
Glue pieces of string into the bottom of another cardboard tube or paper towel roll and pieces of yarn into the bottom of another. Cut these two tubes in half down the center of the tubes width-wise so that they are half as long as the other tubes. Use 1 to 2 or more cardboard tubes or paper towel rolls with nothing added to their insides and set all of the cardboard tubes/paper towel rolls you've made aside.
Affix the cardboard tubes or paper towel rolls you have created to the board with poster putty or another craft adhesive in a pattern that alternates between running right to left and top to bottom, creating a maze for the marble, gumball and other balls to travel through. Tape tube ends together with a piece of tape for tubes that run in the same direction. Place tube ends that run in different directions at 90 degree angles to each other with two edges touching so that the marble/ball running through the maze falls into each tube without falling out of the maze and off the board.
After the maze is dry, raise the board vertically and place it against a chair back. Use a small scale to weigh each ball you will run through the maze and record these weights in a journal.
Drop a marble into the entrance of the maze and use a stopwatch to measure how many seconds it takes the marble to travel through the maze. Repeat this process with all the other balls you have available for the project. Record the maze completion times alongside each weight. Examine which ball traveled fastest and discuss which parts of the maze each ball seemed to move faster or slower over. Consider how mass affects motion and write your thoughts down in the journal. Present the project at your school's science fair along with published information from your class textbook about laws of gravity and physics demonstrated by your maze project.