I. The Gas Burner
A. Gas Burner
The burner is the main source of heat in laboratory. It will be used frequently in your laboratory work. It is necessary that you know how to operate it so you can get the maximum heat from the burner. There are three types of gas burner. There are three types of gas burner namely the Bunsen, Meker and Tirrill types of burners. Get acquainted with the parts and its function.
B. Lighting A Burner
The proper way of lighting a burner is to connect the burner to a gas supply by a rubber tube, turn on the gas and ignite it. To ignite a burner, bring a lighted match upward along the side of the barrel to the top of the burner. Describe the flame. Gradually open the air holes by rotating the collar to admit more air. Observe the distinct zones recognized in the flame.
C. Two Types of Flame: Luminous and Non-Luminous
Place 5 ml of water into a clean dry test tube. Hold it over the yellow flame (air holes are closed) and observe. What is deposited at the bottom of the tube? Repeat the same procedure using a blue flame (air holes are open). Observe and compare results obtained.
II. Glass Manipulation
Place the glass tube flat on the table and measure the desired length. Make a single scratch with 2 strokes of the triangular file. Do not saw. Grasp the tube firmly with both hands, with the thumb opposite the scratch and break the tubing with one snap by pushing with both thumbs away from you.
Attach a wing top or fish tail to the barrel and light the burner using a non-luminous flame. Heat the glass tubing that is to be bent by rotating it slowly over the spread flame. When the glass is already soft, remove it from the flame and make the desired bending.
C. Fire Polishing
This is done to smoothen the cut edge of the glass tubing. Hold the cut end of the tube horizontally in the flame and rotate it slowly until soften and become rounded.
D. Making a Nozzle or Pipette
Use the burner without the wing top in making a nozzle. Heat evenly the portion of the tubing you want to form the nozzle. When the glass softens, remove it from the flame, and pull the end slowly to get the desired capillary size. Scratch with the file and break.
E. Making a Glass Rod or Stirring Rod
In making a glass rod, cut the desired length if the tubing and then heat the ends of the tubing until it is closed.
F. Inserting Glass Tubing in Stoppers
With the tubing and stopper hole with water or glycerol, wrap the hands with a towel or protective cloth for protection. Grasp the tube near the point of insertion. Rotate the tube back and forth while gently pushing it on the stopper. Never attempt to push the tubing through the stopper.