Melting Point Apparatus

Steps in Using it for the Julian NOVA project

Below is a rough draft of the apparatus, its set up, and the step by step procedure used for an accurate melting point determination.

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Step 1, Chemist or technician making capillary tube to hold samples .

Lab apparatus needed

Bunsen burner with wing tip head

rubber gas hose

selection of Pyrex tubing

file for scratching tubing

source of gas for burner

tray to hold samples: small 6 by 8 inches, shallow 1/2 deep and of aluminum, etc…( I'll make one).


These tubes are fairly small and would need close in shots of the operator’s hands working the glass in the flame. The piece of Pyrex tubing is rotated in the flame of the burner. When the flame turns yellow and the tubing begins to soften it is drawn out to a smaller diameter, about 1/8 of an inch. The. tubing is then set aside in the tray to cool. There would have been a number of tubes in process at the same time and therefore a couple already in the tray. When cool each is cut in half making two sample containers. The small end of sample tube is then put back into flame and sealed.

.Still pictures of the various steps or a video.

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Step 2, Filling sample tube.

Lab apparatus needed;

vial containing samples in crystalline form

small spatula

capillary tubing from step 1 and tray for holding samples?

log book for recording* experimental data, pen to write on sample tube and write in log.


Again the parts are small and close in views are needed.

Filling the capillary tube is done with a small spatula and periodically shaking and tapping the sample to the bottom of the tube or holding the tube in one hand while flicking the bottom of the tube with the fingers of the other hand. The viewer needs a very close view of the crystals filling the tube. We recommend sugar for the sample crystals, they are white, close enough to match the shape and will melt to a clear liquid, and are certainly safe. They do however melt at a higher temperature than the actual chemical used by Julian so we will have to be creative and separate the crystal melting and thermometer temperature shots.

* In the world of research, especially patentable product development, it has always been vitally important to keep a complete record of every step in research, product development, and pilot work

.Still pictures of the various steps or a video.

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Step 3, Mounting sample to Thermometer.

Lab apparatus needed.

sample tube


rubber band or “O ” ring

rubber stopper with slit vent,


More close in shots so that the viewer will see the sample being attached to the thermometer close to the bulb of mercury at the end of the column.

.Still pictures of the various steps or a video.

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Step 4, Putting the thermometer and sample into the apparatus,

Lab apparatus needed;

Thiele-Dennis melting point tube with magnifier will already be mounted on a stand.

Bunsen burner with hose for heating the sample.

clamps to hold all the parts

melting point apparatus is on a laboratory bench with other setups.

see overall view picturing the assembled components


Here is an opportunity for the viewer to get an over all view of the whole melting point apparatus and how the operator approaches and handles it.

In actual operation the operator had to exercise reasonable care with the apparatus because at times the melting point tube would have been filled with concentrated sulfuric acid for the bath. This is strong acid, dangerous to most everything and everyone that it touches**. In addition the operator has to be cautious of the lighted Bunsen burner as he/she observes the sample through the magnifier.

The technician adjusts the sample thermometer combination so that the thermometer is facing toward the operator and the sample is visible through the magnifier.

**For example if the operator has to withdraw the thermometer and sample out of the tube he or she must make sure the thermometer does not drip the acid onto the bench or the tech. Our apparatus will be filled with cooking oil but for casual realism it should be treated as though it was acid..

Extra Note; We should have a bottle labeled Sulfuric Acid for the lab scenes.

Still pictures of the various steps or a video.

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Step 5, Operating and adjusting the apparatus .


Locating and adjusting the Bunsen burner is critical to the accuracy and outcome of the measurement. The sample must be raised up to the melting point very slowly to achieve the greatest accuracy

The operator lights the Bunsen burner. The flame height is adjusted so that it is quite low. The operator then slides the burner slowly under the largest diameter portion of the Thiele-Dennis tube , all the while watching the thermometer. If the temperature is rising too rapidly the operator slides the burner away from the tube, if too slowly he slides it toward the tube. My best guess that the whole operation would have taken 10 to 20 minutes or more.

During this time the camera will probably swing from the operator to the capillary then the thermometer and back in some systematic way.

.Still pictures of the various steps or a video.

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