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Measuring Matter International System of Units Scientists use the International System of Units, abbreviated SI units, for measuring matter. The SI unit for mass is a kilogram and for length is a meter. When measuring volume, the liter is the most commonly used unit. 50 60 70 80 90 100 40 30 20 10 100 mL mass - kilogram length - meter volume - liter Prex Kilo One thousand (103) Hecto One hundred (102) Deca Ten (101) Deci One-tenth (10-1) Centi One-hundredth (10-2) Milli One-thousandth (10-3) Micro One-ten thousandth (10-4) Factor 1 meter 1 centimeter Volume Volume is the amount of space that matter occupies. The volume of liquids and gases are typically measured in liters and milliliters. Solids are often measured in cubic centimeters. Density Matter can also be described by measuring its density. Density is the mass of an object in a given volume. To calculate density, divide an object’s mass by its volume. The unit for density is grams per cubic centimeter (g/cm3). To find the volume of an irregularly shaped object, such as a rock, scientists sometimes submerge the object in water to see how much water is displaced. The rise in the water level indicates the volume of the rock. 25 cm 25 cm x 4 cm x 45 cm = 4,500 cm3 4 cm 45 cm 25 cm 25 cm x 4 cm x 45 cm = 4,500 cm3 4 cm 45 cm amount displaced irregular shape = volume 500.00 g 1500.00 g mass = 500 g volume = 200 cm3 density = 2.5 g/cm3 density = 7.5 g/cm3 mass = 1,500 g volume = 200 cm3 500.00 g 1500.00 g mass = 500 g volume = 200 cm3 density = 2.5 g/cm3 density = 7.5 g/cm3 mass = 1,500 g volume = 200 cm3 For example, a piece of aluminum with a mass of 500 g and volume of 200 cm3 has a density of 2.5 g/cm3. A piece of iron with the same volume has a mass of 1,500 g. Iron’s density is 7.5 g/cm3. © Copyright NewPath Learning. All Rights Reserved. 94-4833 Visit www.newpathlearning.com for Online Learning Resources. Prefixes are used to indicate smaller or larger units. For example a centimeter is one- hundredth of the length of a meter. SI units enable scientists to measure matter and share data in a consistent and accurate way. Mass and Weight An object’s mass refers to the amount of matter an object contains, while an object’s weight is the measure of the effect of gravity on its mass. The mass of a person is the same on the Moon and the Earth, but the person weighs less on the Moon than the Earth because the Moon exerts a smaller gravitational force than the Earth. length - meter mass - kilogram 1 meter 1 centimeter volume - liter density = mass volume 600 Newtons 100 Newtons weight Moon Earth gravitational pull 6x stronger

Convert each of the measurements below. 1. 15 kilometers = ____________ meters 2. 2,467 centimeters = ____________ meters 3. 534 meters = ____________ decameters 4. 12.8 centimeters = ____________ micrometers Prex Kilo One thousand (103) Hecto One hundred (102) Deca Ten (101) Deci One-tenth (10-1) Centi One-hundredth (10-2) Milli One-thousandth (10-3) Micro One-ten thousandth (10-4) Factor Pause and Review Using SI units, convert each of the measurements below. © Copyright NewPath Learning. All Rights Reserved. 94-4833 Visit www.newpathlearning.com for Online Learning Resources. 1) 15 kilometers = _____________ meters 2) 2,467 centimeters = _____________ meters 3) 534 meters = _____________ decameters 4) 12.8 centimeters = _____________ micrometers Compare and contrast mass and weight. ______________________________________________________________ ______________________________________________________________ Describe how to determine the volume of an irregular-shaped object. ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ Determine the density of an object if its mass is 250 g and its volume is 25 cm3. ______________________________________________________________ Measuring Matter