How to Make a Rocket Car

Measure a 5-by 5-inch square of cardboard. Mark which sides are the left, right, front and back.

Measure 1 inch from the left and right sides, and draw a dashed line from the front to the back on both sides.

Draw four axle slots about 1/2 inch from all four corners. Line them up with a ruler to make sure that all four are parallel to each other and are perpendicular to the edge of the car.

Trace the outer edge of the empty glass four times to form four wheels. Make sure these are smooth. Use the ruler to find and mark the exact center of the wheels.

Cut out the square base of the vehicle and the wheels. Cut the axle holes out of the walls of the car. Use the blunt edge of the knife or scissors to score the dashed lines—push the edge of the blade against the cardboard, but don't cut through it.

Fold up the walls of the car to form a U-shape.

Pierce one of the wheels with a dowel or skewer, and glue it into place. Make a second unit of these axles. Slide the axles through the holes you cut earlier. Glue the remaining wheels onto the axles, and make sure you don't glue the wheels to the sides of the car.

Cut the bendy straw so that the two ends are the same length.

Insert one end into the mouth of the balloon and wrap the straw with an elastic band.

Glue the straw to the center of the rear car base, leaving about 3/4 inch of the straw hanging off the edge.