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Instructions
Direct Heating with Hot Plates
Place the beaker containing your sample onto a hot plate. Plug in the hot plate and set the heat to the lowest setting necessary for the given experiment. Use laboratory hot mitts or tongs to move hot beakers, and do not move hot beakers unless the experiment requires it.
Keep a watchful eye on the beaker and do not allow any substance to boil over onto the hot plate. Reduce the temperature or shut off the hot plate if this or any other unwanted heating behavior occurs.
Turn off the hot plate and unplug it after you are finished with it and do not allow the cord or anything else to touch the surface of the hot plate -- always assume that the hot plate is active to avoid burns or fires.
Direct Heating with Bunsen Burners
Set up a Bunsen burner and check to make sure that the gas line is secure. Close the air intake openings halfway by adjusting the collar. Place the burner on a ring stand, then set and adjust the iron ring to the appropriate height for the given material and temperature. Place wire gauze on the iron ring stage.
Light a match and turn on the gas, bringing the match slowly over the barrel to ignite the burner. Adjust the collar to open the air intakes until the flame is the desired temperature. Blue flame for 500 degrees Celsius (932 degrees Fahrenheit); roaring blue flame for 700 degrees Celsius (1,292 degrees Fahrenheit).
Use laboratory hot mitts or tongs to transfer the beaker to the wire gauze and begin heating it. Remain by the Bunsen burner at all times while operating it. Snuff the flame by closing the air intake openings and shutting off the gas supply when finished.
Indirect Heating with Hot Plates
Fill a large beaker halfway full with a heating medium -- typically water or sand -- and place it on the hot plate. Plug in and turn on the hot plate until the medium is at the desired temperature.
Use laboratory hot mitts or tongs to place the smaller beaker containing the sample inside the heat medium of the larger beaker. Replace evaporated water as necessary; never allow water to completely boil off inside a beaker. Reduce the temperature setting if the sample becomes too hot.
Shut off the hot plate and unplug it when finished. Use laboratory hot mitts or tongs to move the smaller beaker first, making sure to allow any heating medium to drip from the glass before transferring it elsewhere. Move the larger beaker once the first is secured and dispose of the heating medium according to your laboratory's guidelines. Typically water is disposed of and sand is reused.
Indirect Heating with Bunsen Burners
Set up your Bunsen burner, adjust the iron ring stage and place wire gauze on the iron ring stage. Fill a large beaker with the desired heating medium and place it on the stage. Place the smaller beaker containing the sample within the heating medium of the larger beaker.
Make sure that the beakers are firmly nested and secured, then turn on the gas supply and light the burner. Adjust the flame temperature as necessary by adjusting the collar of the burning. Replace any water that is boiled off during the procedure.
Close the air intake openings by adjusting the collar to snuff the flame. Shut off the gas supply. Remove the smaller beaker carefully from the heating medium with laboratory hot mitts or tongs, making sure not to disrupt the larger beaker and make it fall from the stage. Remove the larger beaker with hot mitts or tongs only when the first beaker is secure.