How to Make a Car for Physics Class That Is Powered by a Fan?

Draw or mark a base on a piece of cardboard or on an empty plastic bottle. Mark the points where you'll attach the axles, and where you'll build the sail. If you're using cardboard, the base should be at least 3 by 5 inches. You have some leeway on the size and shape of the car. Experiment with different styles.

Cut out the base to your specifications.

Trim the straight straws to the width of the car base. Dab glue along the entire width of the base, and stick the straws into place. You can glue the straws toward the front and back ends of the base, or more toward the middle, as you wish. The important thing is that they are parallel with each other so the car rolls straight.

Trim the dowels with a utility knife or scissors so they are slightly longer than the straws you have glued to the base. About 1/2-inch extra on each side will allow the wheels to attach correctly and roll smoothly. These dowels form the car's axles.

Attach a toy wheel to the end of an axle with glue. If you don't have wheels, you can make some by tracing the mouth of a glass on cardboard. Mark the center of the circle, and cut out the circle smoothly to make a wheel. You can reinforce the wheel with a second or third layer of cardboard glue to the back.

Slide one dowel into one of the straws. Glue another wheel to the other end of the dowel. Repeat this process to attach the other axle to the car.

Mount a flexible drinking straw or tongue depressor to the front-right of the car with glue so that it sits upright at a 90-degree angle to the car base. Repeat on the front-left with the other straw or depressor. These form the masts for the car's sail.

Cut out a piece of construction paper that fits between the two masts. Spread glue along both of the masts, then attach this sail to them, giving it a slight forward curve. Leave the car to dry overnight.

Place the car in front of a fan and switch the fan on to send the car sailing across the floor.