Mass and Volume Butler Middle School 8th Grade Science Bob, Paul, Ms. Adams Oct 2, 2012

Distance Area

Volume and Space Space is all around us Space is three-dimensional (3d) 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 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 = 10cm x 3cm x 4cm = 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 8th grader has a mass of about 45,000 to 50,000 grams A typical car has a mass of about 1,000,000 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 18mL, not 18.5 mL 52.8 ml

Optional: Calculate Volume of Marble & 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