When a fluid flow increases in velocity, normally it is the pressure which decreases. Because the gas in a Bunsen burner is flowing through the chimney, it has a lower pressure than the static air surrounding it.
This difference in pressure causes air to be drawn into the air hole as the gas flows past it, a phenomenon known as the Venturi effect.
As the air hole is opened the flame progresses from an unsteady orange flame to a more steady orange, a steady purple and finally a roaring blue flame. This progression results in increasing flame temperature. The unsteady orange flame produced when the air hole is completely closed is highly visible and of lower temperature. The gas inlet connects the Bunsen burner to the gas jet through a rubber gas intake tube. A spark lighter is commonly used for igniting the combustion of the gas and air.
To ensure that you have the hottest, cleanest flame possible, make sure your rubber tubing is securely connected to the gas jet and to the gas inlet valve. A heatproof mat can be placed under the Bunsen burner as an extra safety precaution to prevent damage to your bench top and to catch stray sparks.
Before lighting, place the Bunsen burner at least 12 inches in front of any overhead shelving or equipment and be mindful of loose hair or clothing, like your lab coat.
Always keep safety equipment, like fire extinguishers and safety blankets, close at hand. Now begin turning the collar counterclockwise. As the collar opens, two distinctive flames appear. The blue outer flame is hotter than the safety flame and makes no noise. This flame can be difficult to see, so be careful when the burner is in this state. The blue inner flame burns the hottest, particularly at the tip. Once you have adjusted the collar to get the flame at the desired temperature, open or close the needle valve to increase the size of the flame or close it to make it smaller.
Metal instruments sometimes need to be quickly sterilized before use or between steps of an experiment. Metal spatulas and inoculation loops, for example, are frequently sterilized between bacterial samples.
Scissors and forceps can be dipped into alcohol and then flamed for rapid sterilization before surgery. Glass instruments, such as serological pipettes, are also frequently briefly flame-sterilized before and between each use.
The Bunsen burner flame can be used to help maintain a sterile field around the openings of experimental containers. By briefly flaming the neck of the container a heat, or convection, current is created.
Convection currents also serve to lift particulates in the air away from the experimental area, so the Bunsen Burner helps to keep the area around the experiment, sterile. For microscopy, glass slides are sometimes passed through a Bunsen burner flame to remove any dust particles before samples are mounted. One interesting application of the Bunsen Burner is using heat to modify glass and metal tools. For example, this thin glass rod is being carefully heated and then bent while the glass is still hot to make a bacterial culture spreader.
Bunsen burner flames can also be used for pulling pipettes, bending pipettes, polishing glass capillary tubes , making glass dissection needles, and sealing a wire pick into a glass pipette.
In this video we reviewed: what a bunsen burner is and how it works, how to adjust a Bunsen burner flame, some safety concerns, and some different applications of your Bunsen burner. Thanks for watching, and remember, only you can prevent laboratory fires! Subscription Required. Please recommend JoVE to your librarian. General Laboratory Techniques.
Introduction to the Bunsen Burner. To learn more about our GDPR policies click here. If you want more info regarding data storage, please contact gdpr jove. As heat rises, microorganisms and dust particles are forced upward and away from the immediate work area.
Creating an updraft with the Bunsen burner minimizes the possibility of microorganisms and dust falling onto the bench or into open bottles, tubes or flasks in the work area.
What is the difference of a hot plate and a Bunsen burner? Actually, the hottest part of the candle flame is the blue part, at degrees F C.
That is where the flame has the most oxygen and you are getting complete combustion. The reddish part is the coolest part, about F C. A Bunsen burner flame produces energy from burning gas.
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