A STUDY IN UNITS OF VOLUME Many chemistry classes at present include students who have not had a course in physics, and are therefore unfamiliar with metric units of measure. I t is also true that a considerable number of students who have had a course in physics come to the work in chemistry with a more or less hazy idea of the actual value of metric units of weight and volume. The work outlined herewith has been set up for the purpose of helping students acquire a clearer idea of the two common metric units of v o l u m e t h e liter and cubic centimeter. The work consists of the construction of three cardboard measures. They are the liter, the cubic centimeter, and the quart. The construction of a quart measure was included in the work for use in making a comparison of the values, quart and liter. I t is surprising to find that with the majority of students, the value one quart is explained in terms of a milk bottle. The construction work was carried on outside the class-room from mimeographed direction sheets, a copy of which is given below. The finished measures were presented to the instructor for inspection and after being checked were then returned to the student. The measures were kept by the students for any future use and finally were entered in an exhibit of class work. The results obtained were, from a mechanical standpoint, quite satisfactory and the students seemed interested in doing the work. It may be in the nature of an assumption to say that the students now have a better idea of these metric volumes than they otherwise would have, for we do not have any exact way of determining the value of the idea that has been established. However, the seeming ease with which they use the terms in their work may serve as an index to indicate that the terms are not just formal words. An example of this use of terms may be cited in the conversion work from cubic centimeter values to liters, and vice versa in which students appeared to have little trouble. THE DIRECTION SHEET
(COPY) Students in chemistry have occasion to use two metric measures of volume. These measures are the cubic centimeter and the liter. Do you know the approximate amount of sugar or sand that would be required to fill a measure of 1 cubic centimeter volume? Do you know which is the larger, a quart measure or a liter measure? The following piece of work is provided to help the student acquire a clear idea of the actual values of these two important metric measures of volume. The work consists of constructing several cardboard measures. It is suggested that you construct the liter measure first, as the s m d size of the cubic centimeter measure might cause some difficulty until you become more familiar with the work.
The Liter Meesure Secure a sheet of light weizht cardboard about 50 centimeters (20 inches) long hy nhout 23 ccntimetrr\ (10 inchrs) wide. Lay off on this eardboud a drawin): smilnr to the dinrram Lelow. l'he dimensions of each square arc 111 centimeters hy II, crxltimeters. Be exact in all measurements. Cut out the diagram along the heavy solid lines. Fold on the dotted lines. You will be able t o fold the work more neatly if you first crease the dotted lines by drawing the blunt edge of a knife blade along each dotted line. NOTE-Use a ruler in tracing the dotted lines and he careful that the cardboard is not cut by the knife blade. After folding the box along the dotted lines, apply library paste or mucilage to the tabs marked: "X, X-1, X-2, and X-3." Now fold the box into shape and firmly press
"Tab X" into place. This will hold the box in shape. Continue by joining Tabs "X-I, X-2, X-3" t o the sides of the box. Press firmly together. Allow paste to dry. (Apply all tabs on outside of box.) The box, if carefully constructed, will have a volume of 1 liter. Label on one side of the box.
The Cubic Centimeter Measure Proceed as in the construction of the liter measure. The dimensions of each small black in your diagram are 1 centimeter by 1 centimeter. Cut out, fold, and paste. After allowing it to dry label-"1 CUBIC CENTIMETER." The Quart Measure Proceed as in the construction of the liter and cubic centimeter measures, laying off the diagram on lightweight cardboard. The dimensions of each block in the diagram are 9.8 centimeters hv 9.8 centimeters (approximate dimensions which are sufficiently . .. accurate for this work). Cut, fold, and paste. Allow t o dry and then label "1 QUART." The measures when completed should be presented ta the instructor for inspection and approval. When the instructor returns the measures to you, reserve for further use. Answer the following questions: 1. Of the three measures which you haveconstructed which is the largest? 2. Assuming that there would be no loss of space, how many of the cubic centimeter measures could be exactly placed in the liter measure? 3. Which has the -=eater volume-the liter measure or the quart measure? 4. Calculate the number of cubic centimeters in 10 liters. 5. Calculate the volume of 2653 cubic centimeters in terms of liters.
