Laboratory exercises to accompany Carhart and Chute's First principles of physics . n a ring stand (Fig. 77). Melt theacetamid by heating the water. As soon as it is com-pletely liquefied the thermometer should be inserted in theacetamid, so that the bulb shall be entirely covered. If necessary, continue to apply heatuntil the temperature is above90° C, but not over 95° C. Inall readings, tenths of a degreeshould be estimated. Remove the burner and thebeaker of water, and allow thetube to cool in air, without be-ing disturbed in any way. Everyhalf minute take a reading of thetemperature. The t
Laboratory exercises to accompany Carhart and Chute's First principles of physics . n a ring stand (Fig. 77). Melt theacetamid by heating the water. As soon as it is com-pletely liquefied the thermometer should be inserted in theacetamid, so that the bulb shall be entirely covered. If necessary, continue to apply heatuntil the temperature is above90° C, but not over 95° C. Inall readings, tenths of a degreeshould be estimated. Remove the burner and thebeaker of water, and allow thetube to cool in air, without be-ing disturbed in any way. Everyhalf minute take a reading of thetemperature. The tube shouldbe closely watched at all times,and at the instant solidificationbegins, a reading should be takenand marked S in the table, todistinguish this point. Continuethe readings at half-minute inter-vals, until solidification is com-plete, and then at one-minuteintervals until a temperature ofabout 55° C. is reached. At the close of the experimentthe tube and thermometer should be returned to the in-structor, without any attempt to remove the thermometerfrom the Fig. 77. COOLING THROUGH CHANGE OF STATE 215 Record the observations in tabular form near the top ofthe left-hand page. Observations Time in minutes 0 ^ 1 1J 2 2|-, etc. Temperature in ° C. — — —? — — —, etc. An outline drawing of the apparatus and a brief descrip-tion of the operations should be placed immediately belowthe table of readings. Curve. — On a sheet of cross-section paper, plot a curvefrom your readings. Allow two horizontal spaces (2 mm.)for a half minute, and one vertical space (1 mm.) for onedegree. This curve is to be pasted by its edge to the topedge of the right-hand page. Discussion: Answer each question with a complete sentence. Is there any point where the temperature curve takes asudden change ? Does this correspond to any change inthe condition of the acetamid ? Does your curve indicatethat acetamid has a definite melting (or freezing) point ?If so, at what temper
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectphysics, bookyear1913
