Put on the safety glasses before you embark on the procedure. Safety always comes first whenever you are carrying out any experiments dealing with chemicals.
Connect the two plastic tubes with even ends to the two vents on the T-valve and the flared one to the remaining vent with the flared end pointing away. Insert the one-way valve on the unused end of one of the other two tubes and the syringe nozzle to the end of the other un-flared tube to complete the construction of your very own air pump.
Break carefully both tips of the gas sampling tube using the pliers. Sampling tubes are made of glass and are calibrated along their lengths in either cubic centimeters or in milliliters. Inside them are different chemicals depending on the gas they are used to measure. Carbon dioxide gas samplers contain hydrazine hydrate that changes its color to blue when mixed with CO2 gas.
Connect the flared end of the air pump to the sampling tube's end with the arrow pointing towards it. The arrow indicates the direction the gas being sampled should flow. Pull the syringe plunger up to the 100 ml mark to suck only 100 ml amount of air through the tube. Repeat this nine more times to add up to one liter of air that passes through the tube while observing along the tube's length.
Observe as the hydrazine hydrate turns blue along the length of the tube toward the end with the pump. The more you pump, the longer the blue trail gets. Toward the syringe end, the blue trail seems faded as opposed to at the origin where it's deep blue in color. Read the measurement at the point where the blue trail ends on the calibrations to get the amount of carbon dioxide present in a liter of the air sample.