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Name: _____________________________ Date: ____________ Period: ____ DENSITY WORKBOOK Question: What is Density? Answer:Density is a measure of how much mass is contained in a given unit volume. Put simply, if mass is a measure of how much 'stuff' there is in an object; density is a measure of how tightly that 'stuff' is packed together. The principle of density was discovered by the Greek scientist Archimedes. Overview of Density Worksheet Key formulas/Concepts: Density – Density = Mass divided by Volume (D = M/V). The mass of an object is 25 grams. The volume of an object is 5 cm3. D = 25g/5cm3 = 5 g/cm3. Volume of a rectangular shaped object/cube – Length X Width X Height (L X W X H). Example – A cube has a length of 3 cm. (Note – a cube has six equal sides). V = 3 x 3 x 3 = 27 cm3. A piece of wood has a length of 10 cm, width of 18 cm, and height of 3 cm. V = 10 x 18 x 3 = 540 cm3. Volume of an irregularly shaped object – Use a graduated cylinder filled with a fluid. Record the beginning amount of fluid (in mL – milliliters). Drop the object into the graduated cylinder. Record the level of the fluid with the object (in mL). To determine the volume: Level of fluid with object (minus) beginning amount of fluid. Example – a graduated cylinder is filled to the 30mL mark with water. You drop in a rock. The water level rises to 48mL. V = 48mL – 30mL = 18cm3. KEY NOTE A submerged object displaces a volume of liquid equal to the volume of the object. One milliliter (1 mL) of water has a volume of 1 cubic centimeter (1cm3). Problems (Always Show Your Work and units – g, mL, cm3, g/cm3, g/mL): __________1. M = 34g, V = 17cm3 __________2. M = 42g, V = 28cm3 __________3. You have a box that has a volume of 210 cm3 and mass of 42g. What is its density? 1 __________4. Calculate the density of a 1440 g rectangular block with the following dimensions: length=8 cm, width=6 cm, height=5 cm. __________ 5. One side of a cube is 6 cm long. Its mass is 259.2 g. What is the density of the cube? __________6. You are given a cube with a length of 2.5 cm, a width of 2.5 cm, and a height of 2.4 cm. You place it on a scale, and its mass is 297 g. Calculate the density. __________7. You have a piece of balsa wood that is 45 cm long, 8 cm high, and 4 cm wide. It has a mass of 720 g. What is its density? __________8. An irregular object with a mass of 120 g displaces 25mL of water when placed in a graduated cylinder. Calculate the density of the object. __________9. The mass of a bead is 15 g. You place it in a graduated cylinder that has 20mL of water in it. After placing the bead in the cylinder, the water level is now at 30mL. What is its density? __________10. A screws mass is 10 grams. After dropping it in a graduated cylinder, you find its volume is 7mL. What is its density? 2 __________11. Drop a toy car in a graduated cylinder with 15mL of water. You look at the level after the car is in the cylinder and see that it is now 32mL. The cars mass is 204 g. What is its density? 12 – 14. Will it float, neither float nor sink, or sink? 15 – 17 Will it float, neither float nor sink, or sink? __________18. A sample has a mass of 6.6g and a volume of 1.1cm3, what is its density? __________19. A piece of metal has a mass of 37.35g and has a volume of 24.9cm3. What is its density? __________20. If a sample has a volume of 5.25cm3 and a mass of 68.25g, its density would be. 3 Limits of measurements: possible reasons for different measurements. 1) Human error. 2) Instruments can only measure to a certain level/degree of accuracy. 3) There is no perfect measuring instrument. 4) Average out Quantitative Data for most accurate information. The mean is the average of the numbers. It is easy to calculate: add up all the numbers, then divide by how many numbers there are. In other words it is the sum divided by the count. Example: What is the Mean of these numbers? 6, 11, 7 Add the numbers: 6 + 11 + 7 = 24 Divide by how many numbers (there are 3 numbers): 24 / 3 = 8 The Mean is 8 Calculate the mean/average for the following data points: 1) 23, 15, 8, 12, 26, 5, 22, 9 = Mean = 5) 4.2, 26.14, 18.95, 12.05, 39.48, 25.26, 13.01 = Mean = 2) 81, 69, 72, 80, 67, 62, 78, 74, 71, 86 = Mean = 6) 69.11, 94.5, 88.93, 75.12, 67.69, 93.07, 86.23, 71.7, 92.8, 57.5 = Mean = 3) 54, 38, 52, 51, 49, 46, 39, 53, 47, 42, 52, 41 = Mean = 7) 77.4, 85.2, 69.54, 54.23, 71.09, 66.87, 71.9, 93.62, 68.15, 50.02 = Mean = 4) 61, 45, 52, 48, 53, 49, 57, 46, 60, 54, 58 = Mean = 8) 11.87, 29.14, 7.5, 4.39, 28.12, 5.8, 16.23, 10.92, 22.01, 15.8 = Mean = 4