Mass and Volume Butler Middle School 8 th
Mass and Volume Butler Middle School 8 th Grade Science Bob, Paul, Ms. Adams Oct 2, 2012
• Distance • Area
Volume and Space • Space is all around us • Space is three-dimensional (3 d) • Volume is amount of space - liter is basic unit for measuring volume • 1 liter(l) is a common size - many drink containers are 1 liter bottles
The big liter • The prefix milli means 1/1000 • To measure smaller volumes we use milliliters (ml) • 1 ml = 1/1000 l = 0. 001 l
The Liter is related to the Meter 10 cm = 1/10 m • A cube, 10 cm on each edge is a liter • This liter-cube has a volume of: 10 cm x 10 cm = 1000 cubic centimeters • 1 liter = 1000 cc or 1 cc = 1/1000 l = 1 ml • We can use cc or ml - they are the same
Measuring Volume • For regular shaped objects like a block, we can calculate Volume • Block: V = L x W x H = 10 cm x 3 cm x 4 cm = 120 cc
Volume by Displacement • Calculating volume of irregular shaped objects is difficult • Measuring water displacement is a simple way of getting the volume of an odd shaped object • Volume of object is the volume of displaced water: Vol = 265 cc - 200 cc = 65 cc
Mass and Matter • Matter is Stuff all around us - Chairs, Tables, Students. . . - all matter takes up (occupies) space - empty space has no matter • Mass is amount of matter in something - gram is basic unit for measuring mass • 1 gram is small - 1 penny is about 3 grams • Mass of an object does not change, unless some matter (stuff) is removed or added to the object
Weight • Weight is the pull of the earth’s gravity • Mass and weight are not the same • All matter on the earth has weight • Weight is a force, it is not measured in grams • Weight can change because gravity changes on earth and all throughout the universe • More on weight later in the year
The little Gram • An average 8 th grader has a mass of about 45, 000 to 50, 000 grams • A typical car has a mass of about 1, 000 grams • A pack of hot dogs has a mass of about 500 grams
“The big Kilo” • A more convenient unit of mass is the kilogram or sometimes called “a kilo” • 1 kilogram (kg) = 1000 grams (g) • The prefix kilo in front of anything means 1000
Measuring Mass • We measure an unknown mass by comparing it to a known mass Triple beam balance
Todays Lab Measure Mass & Volume of Test Objects • Use Triple Beam Balance to Measure mass • Measure Length, Width, Height of wood block, calculate Volume = L x W x H • Use Displacement Method to calculate volume of the other objects
Using Triple Beam Balance • Slide the mass on each beam until you get to balance • Add the 3 masses to get mass of test object Notch
Reading the Graduated Cylinder Liquids in glass containers curve at the edges This is called the meniscus 18 m. L, not 18. 5 m. L 52. 8 ml
Cylinder and compare with displacement method
Common fraction-decimal equivalents and prefixes 1/2 = 0. 5 1/4 = 0. 25 1/8 = 0. 125 1/16 = 0. 0625 1/32 = 0. 03125 1/10 = 0. 1 deci 1/100 = 0. 01 centi 1/1000 = 0. 001 milli 1000 = kilo Num Convert any fraction Den to a decimal Den Num
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