2What is Mass?Mass is the measure of the amount of matter in an object.Mass and Weight are different. Weight is the amount of gravitational force pulling on an object.Weight can also change from place to place (planet to planet), but mass always stays the same.
3Metric Units of Mass Measurement Gram (g) – Unit of measurement (starting point)Milligram (mg) – (1 thousandth of a gram, 0.001, 10-3)Centigrams (cg) – (1 hundredth of a gram, 0.01, 10-2)Decigram (dg) – (1 tenth of a gram, 0.1, 10-1)Decagram (dag) – (ten grams, 10, 101)Hectogram (hg) – (1 hundred grams, 100, 102)Kilogram(kg) – (1 thousand grams, 1000, 103)
4• The units decigram, decagram and hectogram are not used as much as the other units. Grams are used to measure the mass of larger things such as candy bars.Kilograms are used to measure the mass of even larger objects like cars.
5Metric ConversionsTo convert larger units to smaller ones , you MULTIPLY by units of 10To convert smaller units to larger ones you DIVIDE by units of 10Example:To convert 2 grams to centigrams (1 hundredth of a gram), you multiply by 100:2 x 100 = 200 cg (2 grams = 200 centigrams)To convert 3 milligrams (1 thousandth of a gram) to grams, you divide by 10003 ÷ 1000 = g (3 milligrams = g)10001001010.10.010.001KilogramhectogramdecagramUnit(gram)decigramcentigrammilligram
6ORFind out how far apart the two prefixes are on the line above. For example, kilo and hecto are one place apart, kilo and deca are two places apart, etc.Move the decimal point to the left to convert smaller units or right to convert larger units by the number of places you found in the previous step. If there is no decimal in the number, assume it's after the last digit in the number.10001001010.10.010.001kilogramhectogramdecagramUnits(grams)decigramcentigrammilligram
7Example #1To convert 1 kilogram to grams (convert larger to smaller), move the decimal 1 place to the RIGHT and add zeros where needed for the number of places you move down the table.1 kilogram = 1000 gramsDecimal PointStartEnd1kilogramhectogramdecagramgramdecigramcentigrammilligram
8Example #2To convert 1 milligrams to grams (convert smaller to larger), move the decimal 1 place to the LEFT and add zeros where needed for the number of places you move down the table.1 milligram = gramsDecimal PointStartEnd1kilogramhectogramdecagramgramdecigramcentigrammilligram
9Convert the following measurements 8 grams to centigrams _________6.568 kilograms to grams _________2 grams to milligrams _________9.85 centigrams to grams _________4 decigrams to grams _________5 milligrams to decigrams _________800 cg6568 g2000 mgg0.4 g0.05 dg
10_______ + ______ + _______ = ________ g How to Measure MassYou can use a triple-beam balance or hanging balance to find the mass of various objects.The objects are placed on the pan and then you move the weights on the beams until you get the lines on the right-side of the scale to match up.Once you have balanced the scale, you add up the amounts on each beam to find the total mass.What would be the mass of the object measured in the picture?_______ + ______ + _______ = ________ g300703.4373.4
11How to Use a Triple-Beam Balance 1st – Place the object on the pan.2nd – Slide the large weight to the right until the arm drops below the line. Move the rider back one groove. Make sure it “locks” into place.3rd – Repeat this process with the top weight. When the arm moves below the line, back it up one groove.4th – Slide the small weight on the front beam until the lines match up.5th – Add the amounts on each beam to find the total mass to the nearest tenth of a gram.
12How to Use a Hanging Balance 1st – Place the object on the scale.2nd – Slide the large weight to the right until the arm drops below the line. Move the rider back one groove. Make sure it “locks” into place.3rd – Repeat this process with the top weight. When the arm moves below the line, back it up one groove.4th – Slide the small weight on the front beam until the lines match up.5th – Add the amounts on each beam to find the total mass to the nearest tenth of a gram.
13Measuring the Mass of a Liquid -=Mass of beaker with liquidMass of beaker without liquidMass of theLiquid-=7 grams10 grams3 grams
14Find the mass of the following objects on your desk Washer __________Small Density Cube __________Two Large Paper Clips__________50 ml beaker (empty) __________20 ml of water __________5.97 g5.20 g3 g29.10 g18.79 g