Cover any holes in the cardboard box sides with card stock paper, cut slightly larger than the hole. Use masking tape to tape paper in place over the hole. Paint the inside of the box with dark blue paint. Air dry.
Lightly glitter spray paint the box interior. Air dry.
Cut the largest Styrofoam ball into a quarter round with the serrated knife or electric knife. This will be the sun.
Paint the sun yellow. Set one of the cut sides on a piece of wax paper to dry.
Stick one end of nine toothpicks into bars of soap. Stick a Styrofoam ball on the top of each toothpick. Paint the Styrofoam balls in colors representative of the nine planets.
Cut a curved piece of heavy gauge, clear vinyl, the depth of the box and 3 inches wide. This is the base for the asteroid belt. Set the cut vinyl on a flat surface. Dot the vinyl with glitter glue. Make dots in different sizes to represent different asteroids. Leave a little space between each dot. Allow to air dry.
Hot glue the sun to the left-hand inside corner of the box.
Poke nine holes with the finishing nail, along the length of the back of the box, leaving a 4-inch space between the four holes nearest the sun (for the inner planets) and the five holes farthest from the sun (for the outer planets). The 4-inch space is for the asteroid belt.
Insert bamboo skewers in each hole, pulling the skewers through the back of the box. Make the skewers different lengths. Cut off all skewer portions sticking out of the box back with scissors—or break off with hands—to ½-inch. Firmly tape skewer ends on the outside box back with masking tape.
Insert Styrofoam planet balls on the inside-box skewer ends. Use hot glue as needed to secure balls to the skewers.
Secure one end of the asteroid belt vinyl with hot glue to the inside back of the box. The inside, or convex curve of the belt should face the sun.