Matter And Measurement 1 Matter and Measurement
Jan 18, 2016
MatterAnd
Measurement1
Matter and Measurement
MatterAnd
Measurement2
Length
• The measure of how much space an object occupies; The basic unit of length, or linear measure is the meters (m).
MatterAnd
Measurement3
Mass
• The basic unit of mass, or the amount of matter, is the kilograms (kg).
MatterAnd
Measurement4
Volume
• The most commonly used metric units for volume are the liter (L) and the milliliter (mL).□ A liter is a cube 1 dm long
on each side.□ A milliliter is a cube 1 cm
long on each side.
MatterAnd
Measurement5
Temperature:
A measure of the average kinetic energy of the particles in a sample.
MatterAnd
Measurement6
Temperature• In scientific
measurements, the Celsius and Kelvin scales are most often used.
• The Celsius scale is based on the properties of water.□ 0C is the freezing point
of water.□ 100C is the boiling point
of water.
MatterAnd
Measurement7
Temperature• The Kelvin is the SI
unit of temperature.• At 0 K, -273.15 C
(absolute zero) all molecule motion theoretically stops.
• There are no negative Kelvin temperatures.
• K = C + 273.15
MatterAnd
Measurement8
Temperature
• The Fahrenheit scale is not used in scientific measurements.
F = 9/5(C) + 32 C = 5/9(F − 32)
MatterAnd
Measurement9
SI Units
• Système International d’Unités• Uses different units and abbreviations for each
quantity
MatterAnd
Measurement10
Metric System
Prefixes help convert the base units into units that are appropriate for the item being measured.
MatterAnd
Measurement11
Metric System Conversions Factors
King
Henry
Died
By
drinking
chocolate
milk
MatterAnd
Measurement12
Dimensional Analysis
• Equality: An expression that says “this” equals “that”
1 hour 60 minutes
• Conversion factor : A ratio of the equivalent values in the equality
1 hour 60 minutes 60 minutes 1 hour
=
or
MatterAnd
Measurement
Dimensional Analysis• Dimensional analysis : A method of problem-solving that helps
convert between the units used to describe matter
• This “t-chart” format is the same as:
# given units
# given units # find units
ratio of equality/conversion factor
# given units # find units# given units
x
problem
MatterAnd
Measurement
Dimensional Analysis
Example 1: Oak Ridge students attend school from 7:16 am until 2:35 pm. This is 7.32 hours a day. How many minutes is this?
Given: 7.32 hours Equality: 1hour = 60 minutes
Find: # minutes Ratios: 1 hour 60 minutes 60 minutes 1 hour
7.32 hours
or
1 hour
60 minutes
= 7.32 x 60 minutes 1
= 439.2 minutes
MatterAnd
Measurement15
Dimensional Analysis/ Metric Conversions
1) A 5k (km) run is 3.1 miles. How many meters is this?
2) A 10k (km) run is 6.2miles. How many centimeters is this?
=
=
MatterAnd
Measurement16
More Conversion Problems
3) At 20 weeks a zygote is about 17cm. How many millimeters is this?
4) When eyes are dilated for an eye exam they expand 5 mm. How many cm is this?
=
=
MatterAnd
Measurement17
SCIENTIFIC NOTATION
• Because sometimes numbers are just too big or small to work with...........
M. x 10nbase number
exponent
MatterAnd
Measurement18
Scientific Notation
3.254 x 103
• Consists of a number with only ONE DIGIT to the LEFT of the decimal times some power of 10.
base number
exponent
MatterAnd
Measurement19
Standard Numeral to Scientific Notation:
1. Whole numbers will have:Positive power of 10, move decimal to left
Examples: 8,500 = 8 5 0 0. = 8.5 x 103
MatterAnd
Measurement20
Standard Numeral to Scientific Notation:
2. Decimal Numbers will have:negative power of 10; move decimal to right
Examples: 0.789 = 0 .7 8 9 = 7.89 x 10-
1
MatterAnd
Measurement21
Changing from Scientific Notation to Standard Numeral
1. If the exponent is (+): Move the decimal to the right!
Examples: 1.5 x 103 = 1.5 0 0 = 1500
MatterAnd
Measurement22
2. If the exponent is (-): Move the decimal to the left.
Examples: 2.63 x 10-3 = 0 0 2. 6 3 = .00263
Changing from Scientific Notation to Standard Numeral
MatterAnd
Measurement23
MATHEMATICAL CALCULATIONS USING SCIENTIFIC NOTATION
MatterAnd
Measurement24
MULTIPLICATION
A. Multiply base numbersB. Add powers of 10
Example: (1.5 x 103) ( 2.0 X 105) = 3.0 x 108
MatterAnd
Measurement25
DIVISION
A. Divide base numbersB. Subtract powers of 10 (numerator - denominator)
4.0 x 102 2.0 x 104
numerator
denominator
= 2.0 x 10-2
MatterAnd
Measurement26
ADDITION AND SUBTRACTION
*Exponents must be the SAME!
(6.5 x 102) + (2.0 x 103) + (30.0 x 103)
(0.65 x 103) + (2.0 x 103) + (30.0 x 103)
32.65 x 103 = 3.265 x 104
MatterAnd
Measurement27
Every answer should be written in correct scientific
notation!!
632 x 102 = 6.32 x 104
.0754 x 103 = 7.54 x 101
*Move decimal RIGHT = MORE NEGATIVE*Move decimal LEFT = MORE POSITIVE
*ALL NUMBERS IN THE BASE NUMBER ARE
SIGNIFICANT
MatterAnd
Measurement28
Uncertainty in Measurements• Different measuring devices have different uses
and different degrees of precision.
• The more subdivisions an instrument has, the more precise that instrument is.
MatterAnd
Measurement29
Which of the following is more precise? The one with more marks
between the same numbers.A B
MatterAnd
Measurement30
Reading InstrumentsStep 1 - Read the measurement to the smallest subdivision of
your instrument (Subdivision = the distance between two of the smallest lines)
Step 2 - Estimate one more digit
Example: What is the reading of the measurement below? _____
1 2
1.55
estimated digit
MatterAnd
Measurement31
Accuracy vs. Precision
•How close measurement comes to the true value of that measurement.
• How often you get the same measurement; reproducibility; consistent data.
• How close
measurements
are to each other
MatterAnd
Measurement32
Accuracy & Precision Examples
Neither accurate
nor precise
Precise but not
accurate
Precise AND
accurate
MatterAnd
Measurement33
Accuracy and Precision cont…
• Example: Three different groups of students (A, B, and C) measured the mass of the same piece of iron that has a known mass of 5.5 grams.
Which set is both precise and accurate? _______
A B CTrail 1 2.7 4.3 5.6Trial 2 2.7 5.8 5.5Trial 3 2.8 9.2 5.6
C
MatterAnd
Measurement34
Significant Figures
• The term significant figures refers to digits that were measured.
• When rounding calculated numbers, we pay attention to significant figures so we do not overstate the accuracy of our answers.
MatterAnd
Measurement35
Significant Figures
1. All non-zero digits are significant.
2. Zeroes in between two significant figures are themselves significant.
3. Zeroes at the beginning of a number are never significant.
4. Zeroes at the end of a number are significant if a decimal point is written in the number.
MatterAnd
Measurement36
Counting Significant Digits
43.00 m1.010 m9.000 m
1.000 x 103 m 0.01010 m
43,010 m
All of these measurements contain 4 significant digits.
MatterAnd
Measurement37
Calculating Using Sig Figs
1. Multiplying & Dividing1) Multiply or divide to get an answer
2) Round your answer to the LEAST number of SIGNIFICANT DIGITS
Example:
8.02 x 0.43 = 3.4486 = _______3.4
MatterAnd
Measurement38
Calculation practice
• 18.4cm2 / 2.30cm=
• 29.5 m x 3.1 m=
• 15.00 x.00003=
MatterAnd
Measurement39
Calculating Using Sig Figs2. Adding & Subtracting
1) Add or subtract to get an answer
2) Round your answer to the LEAST number of DECIMAL PLACES
Example: 4.3+ 5.4570 9.7570 = ________
MatterAnd
Measurement40
Calculation practice
29.00 99.8
+ 3.0041 - 12 0
0.0098
+ 2.32 0
MatterAnd
Measurement41
Which weighs more a ton of feathers or a ton of lead???
Density
MatterAnd
Measurement42
• The ratio that compares the mass of an object to its volume
• It is an intensive physical property;
• Units: g/mL or g/cm3
Density
Density = Mass 0Volume
MatterAnd
Measurement43
If substances do not mix, the less dense substance will float.
Density
1) What is the density of substance A? _______ 2) What is the density of substance D? _______ 3) If an object with a density of 0.95 g/mL is dropped into the column where would it settle? __________________
Given the densities of the four liquids:
0.69 g/mL 1.26 g/mL 1.00 g/mL 0.82 g/mL
0.69 g/mL
1.26 g/mL
MatterAnd
Measurement44
A block of wood measures 3.2 cm by 4.5 cm
by 6.1cm. When placed on the scale it
weighs 29 g. What is the density?
DensityExample 1
MatterAnd
Measurement45
A marble weighs 15grams. When placed in a graduated cylinder that had a volume of 29 mL of water in it, the water level raised to 34 mL. What is the density of the marble?
DensityExample 2
Final
Initial
MatterAnd
Measurement46
Pure Gold has a density of 19.32 g/cm3. If you have a chunk of gold that weighs 52 grams, what is the volume?
DensityExample 3