4.1: Density Calculations Physical Science GPS Standards: SPS2. Students will explore the nature of matter, its classifications, and its system for naming types of matter. Calculate density when given a means to determine a substance’s mass and volume. SCSh5. Students will demonstrate the computation and estimation skills necessary for analyzing data and developing reasonable scientific explanations. e. Solve scientific problems by substituting quantitative values, using dimensional analysis and/or simple algebraic formulas as appropriate.

Cross out the density unit that is NOT acceptable: density (D) = the relationship between the mass (m) and volume (V) of a substance. acceptable units for mass include grams (g), kilograms (kg), etc. acceptable units for volume include cubic centimeters (cm3), liters (L), milliliters (mL), etc. acceptable units for density include those seen below: Cross out the density unit that is NOT acceptable: g/mL L/kg kg/L g/cm3 Ex1: If 60 g of a liquid occupy a space of 20 mL, what is the density of the liquid? D = m V

Ex1: If 60 g of a liquid occupy a space of 20 mL, what is the density of the liquid? 1. given info & unknown 2. appropriate equation 3. plug in and solve, box answer Three-Step Method: a simple method for solving any equation in science, using the 3 steps described under the areas above. Ex2: If a solid’s density is 2.0 g/cm3 and its volume is 5.0 cm3, what is its mass? D = m V

Ex2: If a solid’s density is 2. 0 g/cm3 and its volume is 5 Ex2: If a solid’s density is 2.0 g/cm3 and its volume is 5.0 cm3, what is its mass? 1. given info & unknown 2. appropriate equation 3. plug in and solve, box answer the volume measurement of a density problem can calculated in two ways: water displacement = method for measuring the volume of an irregular object. an object is dropped into a measured amount of water in a graduated cylinder or beaker. D = m V

the volume measurement of a density problem can calculated in two ways: water displacement = method for measuring the volume of an irregular object. an object is dropped into a measured amount of water in a graduated cylinder or beaker. the difference between the initial volume of the water and the new volume of the water is equivalent to the object’s volume Ex3: A pebble is dropped into a graduated cylinder containing 10 mL of water. The water level rises to 12 mL. If this pebble’s mass is 16 kg, what is its density?

Ex3: A pebble is dropped into a graduated cylinder containing 10 mL of water. The water level rises to 12 mL. If this pebble’s mass is 16 kg, what is its density? 1. given info & unknown 2. appropriate equation 3. plug in and solve, box answer D = m V

measured size = method for measuring the volume of a regular object (such as a rectangular prism, sphere, or cylinder) by measuring the length of the sides/radius. Ex4: A rectangular solid of unknown density is 5.00 cm long, 2.00 cm high and 3.00 cm wide. The mass of this solid is 90.0 grams. Given this information for this material, calculate its density. 1. given info & unknown 2. appropriate equation 3. plug in and solve, box answer

Ex5: A sphere of unknown density has a radius that measures 2. 00 cm Ex5: A sphere of unknown density has a radius that measures 2.00 cm. The mass of this solid is 134 grams. Given this info for this material, calculate its density. 1. given info & unknown 2. appropriate equation 3. plug in and solve, box answer