Shock absorbers are filled with hydraulic fluid. When the 'shocker' is compressed, this fluid is forced by a piston through a small hole in the shock absorber cylinder and into the other end of the unit. The design prevents this action happening quickly, so the spring is restricted from continuing to bounce, helping to keep all four tyres in good contact with the road surface.
Try this simple 'bounce' test. Press down on one corner of your car and let go. Count the number of bounces before the car comes to rest. If the car bounces even twice, your shock absorbers are faulty and should be checked straight away at Fairway Tyre & Auto Services.
Don't put this check off, it could save your life!