LABORATORY MANUAL 17 



EXERCISE X (Textbook 75) 



TESTING THE ACCURACY OF A THERMOMETER 

 AT THE FREEZING POINT 



APPARATUS: Broken ice and water in a tumbler; a 

 laboratory Centigrade thermometer; a common Fahrenheit 

 thermometer brought from home. 



DIRECTIONS FOR WORK: 



(1) Make a drawing of the laboratory thermometer, on 

 the first page of notebook paper. 



(2) Place the bulb of the thermometer in the ice and 

 water; keep it there until the mercury in the tube is station- 

 ary, read to .5 of a degree, and record in degrees C. If 

 below 0, record with the minus sign, as 1 C. Dry and 

 return the thermometer to its case. 



(3) Place a common thermometer in the ice and water as 

 directed in Case 2, (If it has a wooden or metal frame, it 

 will not be injured.) Record the reading in degrees F. to 

 the nearest whole degree. 



Reading of the laboratory thermometer *. C. 



Reading of the common thermometer F. 



RESULTS 



1. What difference did you note between your thermom- 

 eter and the laboratory thermometer 



(a) in regard to construction? 

 (6) in regard to scale? 



(c) in regard to range of temperature (that is, the differ- 

 ence between the lowest and highest readings)? 



(d) Which of these differences affect its usefulness for 

 ordinary purposes? Why? 



2. What is the temperature of melting ice? C.? 



