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
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