Metric System,
Measurement Lab,
Significant Figures
• Objectives:
• Today I will be able to:
• Apply the metric system to making conversions.
• Construct a set of rules for determining
significant figures
• Apply significant figures to problem solving
• Informal assessment – monitoring student
interactions as they complete the What are Significant
Figures activity and practice at their desk
• Formal Assessment – analyzing student responses to
the practice worksheets and exit ticket
• Common Core Connection
• Make sense of problems and persevere in solving them
Lesson Sequence
• Evaluate: Warm Up
• Explain: Measurement Notes
• Engage/Explore: What are significant figures
activity
• Explain: Significant Figures notes
• Elaborate: Significant Figures practice
• Evaluate: Exit Ticket
Warm-Up
• Convert to Standard Notation
• 4.57x 108
• 1.25 x 10-4
• Convert to Scientific Notation
• 60,200,000,000,000,000,000,000,00
• 0.0000527
• Solve
• (3.0 x 104)(4.0 x 105)
• (2.0 x 106) / (1.5 x 104)
Objective
• Today I will be able to:
• Apply the metric system to making conversions.
• Construct a set of rules for determining
significant figures
• Apply significant figures to problem solving
Homework
• Complete significant figures practice
Agenda
• Warm-Up
• Metric System Notes
• What are significant figures activity?
• Significant Figures notes
• Significant Figures practice
Metric
System Notes
The Metric System
•International System of Units (SI)
•Easy to use mathematically
•More divisions – improves accuracy
of measurements
•Used internationally – easier to
communicate
Prefixes
• Giga (G) – 109
• Deci (d) – 10-1
• Mega (M) – 106
• Centi (c) – 10-2
• Kilo (k) – 103
• Milli (m) – 10-3
• Hecto (h) – 102
• Micro (u) – 10-6
• Deka (D) - 101
• Nano (n) – 10-9
• Base Unit – 1
• Pico (p) – 10-12
SI Base Units
• Length = meter (m)
• Mass = kilogram (kg)
- Gram is commonly used (g)
• Time = seconds (s)
• Temperature = Kelvin (K)
• Count/Quantity = mole (mol)
• Electric Current = ampere (A)
• Luminous Intensity = candela (cd)
Derived Units
• Come from combinations of SI base units
• Volume – space an object takes up
- Solids – cubic centimeter (cm3)
- Liquids – Liter (L)
- 1000 cm3 = 1 L
- 1 cm3 = 1 ml
Derived Units
•Density = mass/volume
-
3
g/cm
or
3
kg/cm
or g/ml
Converting Metrics
• Kids Have Dropped Over Dead Converting Metrics
• K = Kilo
• H = Hecto
• D = Deka
• O = One (base unit) – 1 gram, 1 liter, 1 meter
• D = Deci
• C = Centi
• M = Milli
Significant Figures
Notes
Significant Figures
• Measurements are frequently
combined
• Uncertainty of the separate
measurements must be reflected in
your final answer, which is done by
keeping track of the significant figures
in each separate measurement
Significant Figures
•Certain numbers and the
estimated digit of a
measurement
- Ex: 31.7 million has 3 sig figs –
two (3 and 1) are certain, and
one (7) is estimated
What are
significant figures?
Construct a set of rules for determining significant
figures. Work with the students in your row.
Atlantic Pacific Rule
Atlantic Pacific Rule
• If a decimal point is Present as in 52.3
km, count from the “Pacific Side” from
the first nonzero digit to the end.
Meaning, count from the left side of the
number
- 52.3 has 3 sig figs
- How many sig figs in .0093077
- There are 5 sig figs (start counting at 9)
Atlantic Pacific Rule
• If the decimal point is Absent, as in 1530
g, count from the Atlantic Side
beginning with the first nonzero digit
and going to the end, counting any zero
as significant. This means start from the
right
- 1530 g has 3 sig figs
• How many sig figs in 190,542,100ml
- There are 7 sig figs
Examples
• .0026702 m
-5
• 19.0750 kg
-6
• 25,000,000,000
mm
-2
• 1,908,150 L
-6
• 520 ml
-2
• .0102 ns
-3
Sig Fig Calculations
• You cannot be more precise than your
least precise measurement
• In multiplication and division, the
measurement with the smallest number
of sig digits determines how many digits
are allowed in the final answer
• If you have several steps, carry the extra
digits. Only the final answer is rounded
Examples
•6.15 m x 4.026 m = ?
- 6.15 m has 3 sig figs
- 4.026 m has 4 sig figs
- Your answer can only have 3 sig
figs
- 24.7599 m2  24.8 m2
Examples
•.03287 g x 45.2 g = ?
- .03287 g has 4 sig figs
- 45.2 g has 3 sig figs
- Your answer can only have three
sig figs
- 1.485724 g 
1.49 g
Sig Fig Calculations
• When adding or subtracting, the number of
decimal places in the answer should be equal
to the number of decimal places in the number
with the FEWEST places.
• 0.12 + 1.6 + 10.976 = 12.696
• 12.696  12.7 (a number with one decimal
place, because 1.6 has only one decimal place)
Final Note
• When doing calculations with significant figures, conversion
factors do not figure in
• Example: if you are calculating percent error the final step is
to multiple by 100, which technically has one significant
figure. However, 100% is a conversion factor and should not
be used
• Counts and defined numbers are EXACT and have no
uncertain digits
• Example: if you say there are 6 people in your family it is a
counted number and is considered certain. There are not
6.1 people in your family
• Example: 12 inches = 1 foot is defined – do not use
significant figures. 1 foot will never be 11.99 inches. In both
cases, significant figures do not apply
Significant Figures
Practice
Complete the practice at your desk. Whatever you do
not finish will become homework.
Exit Ticket
• Write one multiplication/division problem and
one addition/subtraction problem using
numbers with decimals
• Trade your problems with a partner and have
them solve using the correct number of
significant figures