Determine the amount of liquid that you need for the experiment. The design of the pipette with the bulb at the top, allows you to control precisely how much liquid you need to add.
Take the rubber bulb and squeeze it until it is flat. Before attaching the rubber bulb to the top of the pipette, you have to remove all the air from it. If you do not remove the air from the rubber bulb, then you will not be able to suck the liquid into the pipette for the measurement.
Attach the rubber bulb to the top of the pipette. Once you have squeezed all of the air out of the rubber bulb, attach it to the top of the pipette. Make sure that the rubber bulb is secure.
Press the button on the side of the rubber bulb. The rubber bulb for the pipette has two rubber buttons. One button allows for the liquid to leave the tube, while the other button allows the liquid to enter the tube. The buttons are not always labeled. If the buttons are not labeled, test each one. The harder you press the button, the faster the liquid will enter the tube. Therefore, when you are approaching the proper amount of milliliters, press the button with less force.
Check your measurement. When measuring pipettes, determine the measurement from the bottom of the meniscus. The meniscus is the top portion of the liquid that is concaved down. Once you obtain the necessary amount, record your measurement within your lab notes.
Place the pipette over the container where the liquid for the experiment needs to be poured and press the button on the rubber bulb of the pipette to release the liquid.