1. STANDARDS OF MEASUREMENT Section 2
CHAPTER 1
STANDARDS OF MEASUREMENT
Section 2

2. Units and Standards
STANDARD – an exact quantity that people agree to use to compare measurements
Without a standard you cannot compare measurements

3. Measurement Systems
For a measurement to make sense it must have a NUMBER and a UNIT
5meters, 12seconds, 823grams
Give me 8
English System used in the U.S.

4. Measurement Systems Metric System – based on multiples of TEN
International System of Units (SI) – universally used and understood globally by scientists

5. METRIC SYSTEM BASE UNITS: QUANTITY MEASURED UNIT SYMBOL Length meter m
Mass
kilogram kg
Time
second s
Electric current
ampere A
Temperature
kelvin K

6. METRIC SYSTEM SI Prefixes
SI is easy to use because it’s based on multiples of 10
PREFIXES ARE USED TO INDICATE WHICH MULTIPLE OF 10

7. MEANING (multiplying factor)
METRIC SYSTEM
SI Prefixes
PREFIX
SYMBOL
MEANING (multiplying factor)
Kilo- k
1,000
Deci- d
0.1
Centi- c
0.01
Milli- m
0.001
Micro-
Nano- n

8. METRIC SYSTEM Converting from one unit to another
Need to use a CONVERSION FACTOR: a ratio that is equal to ONE and is used to convert from one unit to another
Convert 1gram to milligrams:
1g x 1,000mg/1g = 1,000mg
Convert 10meters to kilometers
10m x 1km/1,000m = 0.010km

9. MEASURING DISTANCE LENGTH – the distance between 2 points METER (m)
When choosing the unit, make sure it’s appropriate.

10. MEASURING MATTER MASS – the quantity of matter KILOGRAM (kg)
Depends on number and type of atoms

11. MEASURING TIME How long it takes something to happen SECONDS (s)
Records History

12. MEASURING TEMPERATURE
How much heat something has
KELVIN (K)
but most often reported scientifically in CELSIUS (⁰C)

13. DERIVED UNITS: Volume and Density
VOLUME – amount of space occupied by an object
Derived from 3 measurements;
V = l × w × h = cm3
Liters (L)
1 mL = 1 cm3

14. DERIVED UNITS: Volume and Density
DENSITY – mass per unit volume of a material
Derived from the mass (g) ÷ volume (cm3)
Water is the standard for density 1g/cm3
DENSITY OF SOME MATERIALS AT 20⁰C
WATER
1.0 g/cm3
LEAD
11.34 g/cm3
HELIUM
g/cm³