List an example of things measured
by mass, volume, and length.
Agenda for Wednesday Sept 24th
1. Go over test
2. Measurement notes
3. Measurement practice
Accuracy & Precision
• Accuracy:
– Freedom form mistakes or errors;
Correctness
• Precision:
– The ability to repeat; Repeatability
Units of Measurement
• International System of Units (SI)
Quantity
Base Unit
Abbreviation
Length
Meter
m
cm, mm, km
Mass
Kilogram
kg
g, mg
Time
Second
s
Temperature Kelvin
K
**Celsius (C)
Linear Measurement
(straight lines)
• Length, Width, Height
• Tool:
• Meter stick, ruler
• Base unit of measurement:
• Meters (m)
Area
• How much surface an object covers
• Units:
– m2, cm2 , etc.
• Formula:
– A=LxW
Volume
• How much space an object takes up
• Two types:
– Regular and irregular
• Regular solids are box like
– Volume is found by measuring length, width, and
height
• The volume of irregular objects is found by
water displacement
Volume (cont.)
• Tool:
– Regular = ruler or meter stick
– Irregular = graduated cylinder
• Units of measurement:
– m3, cm3 (for solids)
– L , ml (for liquids)
• 1cm3 = 1ml
Volume of Regular Objects
• Boxes:
–V=LxWxH
• Spheres
– Formula : V = 4/3 πr3
• Cylinder
– Formula: V = πr2 h
– *π = 3.14
Measuring spheres/circles
• Measure end to end
– Use paper on edge of spheres
• Measured diameter we need radius
– Radius = ½ diameter
– So: if d = 10 then r = 5
How many decimals?
What is accuracy? Precision?
Agenda for Thursday Sept 25th
1. Go over test
2. Measurement pre-lab
3. Measurement lab
Volume lab
• Rounding
– What was the smallest number of digits in any of my
measurements?
– You would then round off your calculated value to the
smallest number of digits in your measurements.
Example:
If L = 2.11 cm, W = 4.3212cm and H = 7.10cm,
7.10cm has the smallest number of digits so
your calculated value would be rounded to
three digits.
2.11 x 4.3212 x 7.10 = 64.735897 would be
rounded to 64.7
Three students reported the length
of a pencil to be 12 cm, 12.0 cm,
and 12.00 cm.
Do all three readings contain the
same information?
Which one has the most? Why?
Agenda for Friday Sept 26th
1. Measurement lab
How do you decide how much water is in the
cylinder?
How much water is there?
Agenda for Monday Sept 29th
1.
Volume of Irregular objects
What is the volume of a box with the
following dimensions:
Width = 3.45
Length = 2.56
Height = 1.89
Agenda for Tuesday Sept 30th
1. Finish Measurement notes
2. Metric Conversion Notes
3. Density
Mass
• Definition:
– The amount of matter in an object
• Tool:
– Triple beam Balance
• Base unit:
– Grams (g)
– A penny has the mass of about 1g
• 1g = 1cm3 for water only
Making a connection
• When you use water
(this works only for water)
1 ml = 1 cm3 = 1 g
Weight
• Definition:
– The gravitational pull on an object
• Tool:
– Scale
• Base unit:
– Newton (N)
Mass Vs. Weight
Temperature
• Definition:
– Measurement of the average kinetic energy of
molecules
• Tool:
– Thermometer
• Base unit:
– Celsius (co) and Kelvin (ko)
Density
• Def. – ratio of the mass of a substance to the
volume of a substance
– Formula: D = m/V
• Density = mass/volume
• Units: g/cm3
• Low density means atoms are not as packed
together
Density
• Density determines whether an object will
float or sink
– Less dense objects float
• Water has a density of 1 g/cm3
• Use density to find substances
– lab
Density Problems
• If 12.0 cm3 has a mass of 9.17 g, what is the
density?
• If an object has a density of 4.2 g/cm3 and a
mass of 30 g, what is its volume?
Explain how you would find the
volume of an irregular shaped object.
Agenda for Monday Jan 13th
1. Finish notes
2. Go over worksheet
3. Mass lab
What is the difference between
mass and weight?
Agenda for Tuesday Jan 14th
1. QUIZ
2. Density
3. Start lab
TEST TUESDAY
What is density?
Agenda for Wednesday Jan 15th
1. Demo
2. Lab/worksheet