1. Physical Science Section 1.3
Measurement
Physical Science
Section 1.3

2. Scientific Notation Why is it useful?
Scientific Notation: a way of expressing a value as the product of a number b/t 1 and 10 and a power of 10.

3. really really BIG numbers: really really SMALL numbers:
For example…
really really BIG numbers:
300,000,000 m/s = 3.0 x 108 m/s
The exponent, 8, tells you how many places to the right to move the decimal point
really really SMALL numbers:
m/s = 8.6 x 10-4 m/s
The exponent,-4, tells you how many places to the left to move the decimal point

4. So why is it useful?

5. Math with Scientific Notation
Multiplying: multiply the numbers and add the exponents.
Dividing: divide the numbers and subtract the exponents.

6. SI Units of Measurement aka: the metric system
All measurements REQUIRE a number AND a unit.
Scientists use SI units.
SI=International System of Units
SI is a revised version of the older metric system
Why is it useful for scientists to stick with one system?

7. Base Units SI uses base units and prefixes. Quantity Unit Symbol
Length
meter m
Mass
gram g
Volume
liter l
Temperature
kelvin K
Time
second s

8. Prefixes
Prefixes tell you how much of a base unit you have. For example, a kilo (which means 1,000) liter means 1000 liters.
Unit abbreviations come from the combination of the prefix abbreviation and the base unit abbreviation. For example, a kiloliter is abbreviated kl.

9. Prefix
Symbol
Meaning
giga- G
billion (109)
mega- M
million (106)
kilo- k
thousand (103)
deci- d
tenth (10-1)
centi- c
hundredth (10-2)
milli- m
thousandth (10-3)
micro-
millionth (10-6)
nano- n
billionth (10-9)

10. Why are prefixes useful?

11. Conversion Factors
Conversion factors are used to convert from one unit of measurement to another
A ratio of equivalent measurements
3/3 = ?
67/67 = ?
x/x = ?
1 meter/1 meter = ?

12. Conversion Factors, ctd.
1 meter / 100 cm = ?
100 cm / 1 m = ?
1000 ml / 1 l = ?
These are all conversion factors!

13. Conversion Factors, ctd.
To convert from one unit of measurement to another, multiply the number you want to change by the conversion factor that will change it
Examples?

15. Precision & Accuracy Precision: a gauge of how exact a measurement is
The precision of a calculated answer is limited by the least precise measurement in the calculation.
Accuracy: the closeness of a measurement to the actual value of what is being measured

16. Measuring Temperature
Thermometer = measures temperature
What are units of temperature you are familiar with?

17. oC = 5/9(oF – 32o) oF = 9/5(oC) + 32o
Celsius & Fahrenheit
oC = 5/9(oF – 32o)
oF = 9/5(oC) + 32o

18. Kelvin To convert: K = oC + 273
SI Base unit for temperature is the kelvin (K).
0 K is the lowest possible temperature that can be reached.
0 K = oC
To convert: K = oC + 273