Ryan Hoffman, age 15, of Fargo, N.D., for his question:

WHAT IS A TORSION BAR?

Torsion bar suspension is a method of absorbing shock in automobiles. When a car with coil springs hits a bump, the coils press closer together and absorb the shock. In torsion suspension, a torsion bar replaces the coils in the front end of the car.

A torsion bar is actually a coiled spring that has been straightened. A torsion bar has great elasticity and can withstand the same amount of stress as a spring. But, whereas a spring presses together to absorb shock, a torsion bar is subjected to torsion or twisting.

A torsion bar consists of a steel rod attached to an arm from the front wheel. When the car strikes a bump, the torsion bar twists to absorb the shock. Torsion bars take up less room than coil springs.

A shock absorber is a device also used on automobiles to reduce shock. It is made up of a piston inside a cylinder that contains oil. When the car wheel hits a bump, the piston pushes upward and the oil resists the piston. This resistance to the motion of the piston offsets the force of the bump.