If you want to build a really fast LEGO car, you have to know some simple Laws of Physics. Contrary to popular belief, placing weights on the car will not change the rate of acceleration. The best way to make your LEGO car speedy is decrease the friction and air resistance.
Push together two triangular LEGO pieces to build a pointy nose for your LEGO car. Decreasing the surface area of the front end reduces air resistance.
Attach the triangle shaped front end to the rectangular LEGO piece. The point is the front end and the rectangle is the back end of your car.
Press on small LEGO pieces to firmly connect the front and back end together. The design of your LEGO car should stay long and sleek.
Attach four hard plastic LEGO tires, not rubber tires, on each of the four ends using wheel connection LEGO pieces. Hard plastic LEGO tires create less friction than rubber LEGO tires. Friction is another force that can slow down your LEGO car.
Push car from the rear rectangular end over a smooth surface. The surface can be flat or angled like a ramp.
Try an experiment with air resistance on your car. Under adult supervision, use a stop watch and compare the speed of the car when it must accelerate against the strong wind of a hair dryer. .
Small parts or use of electrical devices can be dangerous around very young children.