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U1D5: Identifying the precision and number of Significant Figures in a measurement.Do Now: 1. Complete Measurement Lab (15 min) (Make sure that I check 1st try BEFORE you move on to 2nd try!)2. Complete: WS “Tools for Measurement” Today:3. To be able to determine the precision of a measure.
(followed by practice)4. To be able to determine the significant figures in a
measure (practice)5. Checkpoint!
Day 3
So….Let's review what we did in the measurement lab
Review Sheet (folder)
Day 5
Day 3
So far so good…Let’s try Practice Packet #2
1 b) Were the measurements for the paper clips the same on each ruler? Explain
Day 3
What the heck are significant figures?
• Good question……• Significant = important• Figures = numbers• Aren’t all numbers important?– Not always
Day 5
Significant Figures
• aka: Reliable Numbers in a Measurement!
• In expressing the results of a measurement, one estimated figure is considered significant or reliable.
• The numbers that you record when doing a measurement are ALL reliable!
Day 3
To determine precision, we need to know Place Value!
Day 3
What is precision?• 2 meanings in science:–How close measures are to each other
(repeatability of data) – The number of digits to which a value has
been reliably measured.
• So… you tell me the rules of precision
Day 3
Find the pattern. Circled numbers are the level of precision. What’s my rule?
• 237.4653 g 100.001 cm 2 000 000 KL
• 1700 mm 0.0043 j 0.1 L
• 6300 Kg 750 000 Kj
Day 5
Rules for Determining Precision:
1) Decimal present:
2.10 g 136.111 g 5.1234 g 212 g 10.g
2) No decimal present:
3500 km 3500 km 120 km
the precision is the place furthest to the right ->
the precision is the place value of rightmost non-zero or zero with a line (bar) over it
Day 3
Practice
1. 734 g precision: _______________2. 5073.0 cm precision: _______________3. 150 mm precision: _______________4. 0.04 ml precision: _______________
Day 3
Significant figures: digits recorded by the measuring devise
A significant figure is ANY digit that is NOT a place-holding zero.A) SF:PH
(>1)B) 0.PH:SF (<1)
C) SF.SF
1000 0.21 1.071000 0.210 91.2051000 0.0013 1000.32000 0.00130 128.00032000 0.001030
The place occupied by the rightmost sig fig.Precision: the place the measuring device is read to.
Day 5
Rules for Sig Figs
1. Numbers less than one-> begin with 1st non zero and go right
ex. 0.043 mg -> 0.043 mg # s.f = _______ 0.060 L -> 0.060 L # s.f = _______ 0.00053 mm -> 0.00053 mm # s.f = _______
Day 5
2. Numbers one or greater a) no decimal, no line over zero… -> begin w/ leftmost non-zero go to the right most non-zero
12050 mL -> 12050 mL # s.f = _______ 1643 mL -> 1643 m # s.f = _______ 104 mL -> 104 mL # s.f = _______
Day 3
2. Numbers one or greater b) decimal -> all sig figs !!
12050. mL -> 12050. mL # s.f = _______ 1600. mL -> 1600. m # s.f = _______ 1.04 mL -> 1.04 mL # s.f = _______
Day 3
2. Numbers one or greater c) line over zero… -> left non- zero go to the zero mark
12000 mL -> 12000 mL # s.f = _______ 12000 mL -> 12000 mL # s.f = _______12000 mL -> 12000 mL # s.f = _______12000 mL -> 12000 mL # s.f = _______
Line tells you point of precision! Zeroes after are place holders
Day 3
Cool• Take this time to practice Sig Fig WS #1 and have
me check it
• Practice #2 TONIGHT
• Read page 8-9 in notes packet (vocab on front)