Kevin Nester, age 13, of Cumberland, Md., for his question:

HOW DOES A TORSION BAR WORK?

A torsion bar replaces springs in some cars. Imagine what would happen if you twisted a length of garden hose. After you twisted it, it would pull itself back into shape. This is just how a torsion bar works.

When a car wheel hits a bump, the torsion bar is twisted. The bar then twists itself to help hold the wheel on the road and to keep the car level.

Torsion bar suspension is a method of absorbing shock in automobiles. A torsion bar is actually a coiled spring that has been straightened. The bar has great elasticity and can withstand the same amount of stress as a spring.

A torsion bar is made of a steel rod attached to an arm from the front wheel. It takes up less room than a coiled spring.