Metric System. 321. The names of the units of surface measurement are the same as those used for linear measurement, combined with the word square; thus, a surface equivalent to a square whose side is a meter, is 1 square meter. The pupil, if properly taught to this point, will be able, without difficulty, to fill the blanks in the table of— SQUARE MEAsure. 100 square millimeters (sq. mm.) = 1 square centimeter (sq. cm.). square centimeters square decimeters square meters = 1 square decimeter (sq. dm.). = 1 square meter (sq. m.). NOTE. The special unit of surface measure for measuring land is equivalent to a square whose side is ten meters. This unit is called Metric System. 322. The names of the units of volume measurement are the same as those used for linear measurement, combined with the word cubic; thus, a volume equivalent to a cube whose edge is a meter, is 1 cubic meter. The pupil should be able easily to fill the blanks in the table of — VOLUME MEASURE. 1000 cubic millimeters (cu. mm.) = 1 cubic centimeter (cu. cm.).* NOTE 1.-The special unit of capacity, for measuring liquids, grain, small fruits, etc., is the liter. It is equal to 1 cubic decimeter. 10 liters (1.) = 1 dekaliter (Dl.), and 1 tenth of a liter = 1 deciliter (dl.), etc. NOTE 2.The special unit for measuring wood is the ster. It is equal to 1 cubic meter. * The abbreviation cc. is often used for cubic centimeter. Metric System. 323. The primary unit of weight is the gram. This equals the weight of one cubic centimeter of pure water. NOTE. The special unit for the weight of very heavy articles is the tonneau. It equals the weight of a cubic meter of pure water, or 1000 kilograms. EXERCISE. 1. The weight of 1 liter of water is grams. 2. The weight of 6 cubic centimeters of water is 3. The weight of a cubic decimeter of water is 4. One kilogram of water equals 5. One hektogram of water equals cubic centimeters. CC. -cubic centimeters. 7. If the specific gravity of iron is 7.5, what is the weight of a cubic centimeter of iron? 8. If the specific gravity of cork is, what is the weight of a cubic decimeter of cork? 9. If the specific gravity of oil is .9, what is the weight of a liter of oil? 10. What is the weight of a cubic meter of stone whose specific gravity is 2.5? 11. What is the weight of a cubic decimeter of wood whose specific gravity is .8? Metric System. 324. MISCELLANEOUS PROBLEMS.* 1. Find the area of a rectangular surface that is 1 meter long and 6 decimeters wide. Make a diagram of this surface upon the blackboard. 2. Find the area of a rectangular surface that is 2 decimeters long and 5 centimeters wide. Make a diagram of this surface on your slate or paper. 3. Find the solid content of a 5-centimeter cube. A 5-centimeter cube is what part of a cubic decimeter? 4. Find the solid content of a 4-decimeter cube. A 4-decimeter cube is what part of a cubic meter? 5. Find the entire surface of a 4-centimeter cube. The surface of a 4-centimeter cube is what part of a square decimeter ? 6. Find the area of a rectangular surface that is 2.4 yards by 5 yards; of a rectangular surface that is 2.4 meters by 5 meters. 7. Which is the larger of the two surfaces described in problem 6 ? 8. Find the area of a rectangular surface that is 3.5 yards by 2.5 yards; of a rectangular surface that is 3.5 meters by 2.5 meters. 9. Find the volume of a rectangular solid that is 3.4 feet by 3 feet by 2 feet; of a rectangular solid that is 3.4 meters by 3 meters by 2 meters. 10. Find the volume of a rectangular solid that is 3.5 meters by 2.3 meters by 4.6 meters. 11. What is the weight of a cubic decimeter of wood whose specific gravity is .5? (P. 367.) * Pupils should draw or image 'every magnitude whose dimensions are given on this page. Metric System. 323. The primary unit of weight is the gram. This equals the weight of one cubic centimeter of pure water. NOTE. The special unit for the weight of very heavy articles is the tonneau. It equals the weight of a cubic meter of pure water, or 1000 kilograms. EXERCISE. 1. The weight of 1 liter of water is grams. 2. The weight of 6 cubic centimeters of water is 3. The weight of a cubic decimeter of water is 4. One kilogram of water equals 5. One hektogram of water equals cubic centimeters. CC. 6. One dekagram of water equals—cubic centimeters. 7. If the specific gravity of iron is 7.5, what is the weight of a cubic centimeter of iron? 8. If the specific gravity of cork is, what is the weight of a cubic decimeter of cork? 9. If the specific gravity of oil is .9, what is the weight of a liter of oil? 10. What is the weight of a cubic meter of stone whose specific gravity is 2.5? 11. What is the weight of a cubic decimeter of wood whose specific gravity is .8? |