Transcript Notes Unit 1-4

WARM UP
8-26-13
1. Find the density of this solid,
mass = 180 grams
2. Find the mass of an object if it takes
up 4 cm3 and has a density of 5 g/cm3
3. Find the volume if an object weights
70 grams and has a density of 14 g/cm3
Agenda
Homework
Quiz Unit 1
Notes Unit 1-4
WS Unit 1 Density
Work on online HW
Aug 28 – Online HW unit 1
Aug 31 - Test review WS
Sept 2 – Test unit 1
Unit 1-4
Rounding Measurements

Accuracy- how close a measurement is to
the actual value
Rounding Measurements

Precision- how frequently you get the same
measurement when measuring in the same
way
Rounding Measurements



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Round the following numbers:
5.76 to the nearest tenths
453 to the nearest tens
3.685 to the nearest hundredths
Scientific Notation

Used to make numbers easier to deal with
and to keep track of zeros

Only one number before decimal!

Using calculators with scientific notation:


Number * 10 ^ (exponent)
Number EE (exponent)
Scientific Notation Examples
Assignments

Unit 1 density WS due today before leaving
class

Online HW Unit 1

Test review WS
EXTRA NOTES NOT
APPLICABLE
Significant Figures

Significant figures are used to indicate the
preciseness of measurements
- Significant figures consist of all the digits
known with certainty as well as one
estimated, or uncertain digit
- Use for rounding answers
Rules for Determining
Significant Figures
1. Nonzero digits are always significant
e.g. 643.5 has 4 sig figs
2. Zeros between nonzero digits are
significant
e.g. 909 has 3 sig figs
3. Zeros in front of non zero digits are not
significant
e.g. 0.00034 has 2 sig figs
e.g. 00063
Rules for Determining
Significant Figures
4. Zeros both at the end of a number and
to the right of a decimal point are
significant
e.g. 9.00 has 3 sig figs
5. Assume zero to the right of a number
but to the left of the decimal point is not
significant
e.g. 4000 has 1 sig fig, but 30.0 has 3 sig
figs
Sig Fig Practice
Determine the number of sig figs in each value
a) 4658.2
b) 4006
c) 0.000265
d) 0065
e) 1.0065
f) 3.0
g) 700
Sig Figs in Calculations

When multiplying and dividing, round your
answer to the least number of sig figs in the
equation
Multiplying and Dividing
a) 12 x 4 = ?
b) 1.0 x 623 = ?
Sig Figs in Calculations
When adding and subtracting, round your
answer to the least number of decimal places
in any of the data you are given.
Adding and Subtracting
a)
b)
3.11 + 1.2 = ?
9.899 – 2.23 = ?