measurement - weebly · 2018-09-04 · international system of units (sd si base units name meter...
TRANSCRIPT
Measurem
ent: A quantity that
has both a number and a unit.
-It is important to m
ake m
easurements and decide
whether a m
easurement is
correct.
-International System of
Units (SI)
Scientific Notation: A
given num
ber is written as the product of
two num
bers.
Ex: 10
x
Ex
2: 1023 = ?
Accuracy vs. Precision
Accuracy: M
easure of how close
a measurem
ent comes to the
actual or true value of whatever
is measured.
Precision: Measure of how
close a series of m
easurements are to
one another.
To evaluate the accuracy of a m
easure, the measured value
must be com
pared to the correct value.
To evaluate the precision of a m
easurement, you m
ust com
pare the values of two or
more repeated m
easurements.
Determ
ining Error:
Accepted Value: C
orrect value based on reliable references
Experimental Value: V
alue based on reliable references
Significant Figures: Measurem
ent include all of the digits that are know
n, plus a last digit that is estim
ated.
Measurem
ents must alw
ays be reported to the correct num
ber of significant figures because calculated answ
ers often depend on the num
ber of significant figures in the values used in the calculation.
Conversion Factor: A
ratio of equivalent m
easurements.
-1 cm
= 1m-
1$ = 4 Quarters = ? D
imes =
? Nickels = ? Pennies
Dim
ensional Analysis: A
way to
analyze and solve problems
using units, or dimensions, of
the measurem
ents.
Ex: Daily problem
solving
Converting U
nits:
Analyze- List the know
ns and unknow
ns
Calculate- Solve for the
unknowns
Evaluate- Does that m
ake sense?
Density: ratio of an object’s m
ass to its volum
e.
-M
ass/volume
●A
n intensive property that depends only on the com
position of a substance, not on the size of the sam
ple.