DIAGRAMS FOR SOLVING PHYSICS PROBLEMS

John W. Scoville
1915 School Science and Mathematics  
By means of diagrams it is possible to solve, hard problems in specific heat and heat of fusion in about thirty seconds. These diagrams are useful in checking up the measurements of students in calorimetry experiments; in a few seconds the teacher can tell the student whether the observations are accurate enough to warrant him in going through with the calculations or whether he should repeat the experiment in order to get a new set of data. To make a diagram for'solving problems in specific
more » ... t, draw a horizontal line, about forty-five centimeters long, and divide it into one hundred units. This is the temperature line which is shown in Figure 1 . Above this line and parallel to it, draw lines Itro <u 2.vo s^J § vî . X \ ' re^E^ruKE-^I^N£\ Q \o 70" 6o' Sf^io So" 20*' ; ir ;^; S: ' S3 \ , \^o * c FIG J,w 3ff<FO2 4'tnT z<nro/^-<n»o l<nroig .too (b ,î / V.S. to represent the weight of metal taken and similarly below the temperature line draw lines to represent the weight of water into which the metal is dropped. The spaces between the upper parallel lines will be less than the spaces between the lower parallel lines; the ratio of the width of the upper and lower spaces being the same as the ratio of the specific heat of the metal used to the specific heat of the liquid into which it is dropped. Suppose the diagram is constructed and we wish to solve this problem: 1,500 grams of iron at a temperature of 90 C. is dropped into 350 gms. of water at a temperature of 20 C.; what will be the temperature of the mixture? Insert a pin in the diagram at A to show the weight of the water and the temperature
doi:10.1111/j.1949-8594.1915.tb16368.x fatcat:f4bjaanjr5e6tcc32zxwtmahy4