<img alt="" src="/sites/ContentControl/Tuition%20Listing%20Assets/Honda%20Thailand%20Open%202015%207D%20_MG_2919.JPG" style="BORDER:0px solid;" />
Prior to the 1930s players used the standard wedge for this shot. A common problem would be the resultant digging into the sand caused by the sharp edge on the wedge.
The introduction of bounce changed this. The carefully crafted sole on your wedge acts like a hydrofoil in water and helps prevent the digging caused by the standard wedge.
The result of this clever design is that the player can swing the club so it enters the sand behind the ball, sliding through the sand at a shallow depth to lift the ball from the bunker on a cushion of sand. The club and the ball never actually make contact - the impact is somewhat blunted by the layer of sand between ball and face.
The more sand we take the more this impact is blunted and we therefore need to apply more speed.
Photo from www.golffile.ie