LECTURE 2 Flashcards
A standard unit which is an exact quantity used for comparison when measuring
IMPORTANCE OF MEASUREMENT
- _____ non-numeric form
• _____ (latin) - quality or kind - ____ definite form (usually in numbers)
• ____ (latin) - having quantity as mass, size, volume, etc.
Unit of measurement
Qualitative measurement
Qualitativus
Quantitative measurement
Quantitativus
SIGNIFICANT FIGURES
____ Numbers obtained by counting or form definitions ( A dozen of eggs is exactly 12 eggs)
____ numbers obtained from measurements ( any two swarms would be unlikely to contain the same exact number of bees)
____ are digits believed to be correct by the person who makes a measurement
Exact
Non-exact
Significant figures
____ a quantitative description that includes both a unit and a number (For 100 meters, the meter is a unit by which distance is measured and the 100 is the number of units contained in the measured distance)
____ quantities defined by standards that people agree to use to compare one event or object to another
Value
Units
Rules for Significant Figures
- _____
Ex. 1.3 = 2 SF .615 = 3 SF 2.3489 = 5 SF - _____
Ex. 2006 = 4 SF 3.09 = 3 SF 4007 = 4 SF - _____
Ex. 95.0 = 3 SF 9.50 = 3 SF .950 = 3 SF - _____
Ex. 0.0020 = 2 SF 0.376 = 3 SF 0.00376 = 3 SF - _____
Ex. = 5 SF = 3 SF = 4 SF - _____
Ex. 12000 = 2 SF 12000. = 5 SF
1560000 = 3 SF 1560000. = 7 SF
- The digits 1 to 9 are all significant.
- Zero between non zero digits are significant
- The zero is significant if it is the final digit to the
right of the decimal point and non zero digits. - Zero to the left of the decimal point and non zero digits
are not significant. - The use of bar above zero indicates that the zero is
significant. - When a no. ends in zeros, the zeros are not significant.
a quantitative description that includes both a unit and a number
– For 100 meters, the meter is a unit by which
distance is measured, and the 100 is the
number of units contained in the measured
distance
Value
____– quantities defined by standards that
people agree to use to compare one event or
object to another
Units
____ System of measurement that is used in
the United States but has been replaced in most
parts of the world
____ The common system of reference units used in
science
Has evolved into the International System of
Units (SI units) from the French “Systéme
International d’Unités”.
English system
Metric system
BASE UNITS
1. ____ Meter, m, the distance that light
travels in a vacuum in 1/299,792,458 of a
second
2.
____ Kilogram, kg, the mass of a platinum
iridium alloy cylinder in a vault in France
3. ____Second, s, the duration of
9,192,631,770 periods of the radiation emitted
in a specified transition between energy levels
of cesium133
4. ____ Kelvin, K, 1/273.16 of the temperature
difference between absolute zero and the triple
point temperature of water
Length
Mass
Time
Temperature
____ a fixed and unvarying quantity that is
independent of the object’s location
____ the measure of the earth’s
gravitational attraction for a body
Varies in relation to the position of
an object on or its distance from the earth
Mass
Weight
____defined as the mass per unit
volume of a material
____ – Is the ratio of the
density of that substance to the density of
water at 4 °C
Density
Specific gravity
____Also Known as Dimensional Analysis
• The units must always accompany
the numeric value of a measurement,
whether we are writing about the quantity,
talking about it or using it in calculations.
Unif factor method
