Lawn bubblers provide a way to modify an existing sprinkler system to saturate a localized area. Rather than spraying water into the air over a large area, bubblers squirt water at ground level in a circular pattern, usually covering no more than a few square feet. Bubblers use water efficiently because there is little lost to evaporation or the wind. You can adjust the volume of water and spray distance on all bubblers, but be prepared to get wet -- the best way to adjust them is while they are actively spraying.
Observe the bubbler to determine the method of adjustment. If there is a shiny metal screw in the middle of the bubbler, you will need a flat-head screwdriver to do the job. Otherwise, no tools are needed, as it will be adjusted by hand.
Turn on the sprinkler system to pressurize the line with the bubblers. Automated systems have a "manual" setting that allows a particular zone to be activated on command. Press the "+" key on the timer to set it for five minutes and then turn the dial back to the "run" position.
Turn the screw clockwise to decrease the water volume or counterclockwise to increase. The same goes for bubbles without a screw, but use your hand to turn the entire bubbler cap in either direction to adjust it. Once it is adjusted to the maximum setting, you won't be able to turn it anymore. At the minimum setting, the water flow will cease altogether.