Chapter 1 Measurements in Science and Medicine Flashcards
Define Unit
a measurement with a size that everyone knows or understands and is used as a base for calculating other measurements.
Define Base Unit
The starting point for units. All other units are determined by the defining characteristic of a base unit.
Define Derived Unit
Derived unit is a base unit with a prefix that modifies the value of the base unit.
How can the relationship between a base unit and a derived unit be represented in numerical terms?
a number like 1000 or 1/1000
a power of 10 like 10^3 or 10^-3
abbreviations
How are abbreviations determined for base units and derived units?
abbreviations for base units are the first letter of the unit name.
abbreviations for the derived units are the first letter of the prefix and the first letter of the base unit word
examples:
meter is m
centimeter is cm
Are metric abbreviations upper case or lower case and why?
Provide example
lowercase
because upper case are used for less common derived units
example: Mega is capital M
What is the abbreviation for the prefix micro and why?
micro is written as the greek letter μ (mu) because m is used for milli
What type of unit is Liter and what does it measure?
base vs derived
Liter is the base unit that measure volume, how much space and object occupies.
What type of unit is Gram and what does it measure
base vs derived
Gram is a the base unit that measures mass, how heavy an object is
Define Kilo as a number and a power of 10.
Identify its abbreviation
Provide an example with meter as the base unit.
It represents 1,000 times a base unit or 10^3
abbreviation is lowercase k
kilometer (km) is 1000 meters
Define Deci as a number and a power of 10
Identify its abbreviation
Provide an example with meter as the base unit.
1/10 of a base unit
10^-1
Deci (d)
decimeter (dm) 1/10 of a meter
Define centi as a number and a power of ten
Identify its abbreviation
Provide an example with meter as the base unit.
1/100 of a base unit
10^-2
centi (c)
centimenter (cm) 1/100 of a meter
Define milli as a number and a power of 10
Identify its abbreviation
Provide an example with meter as the base unit.
1/1000 of a base unit
10^-3
milli (m)
millimeter (mm) 1/1000 of a meter
Define micro as a number and a power of 10
Identify its abbreviation
Provide an example with meter as the base unit.
1/1,000,000 of a base unit
10^-6
micro (μ)
micrometer (μm) 1/1,000,000 of a meter
What alternate abbreviation might be used for micro instead of μ?
mc
define Volume
the amout of space something takes up
can the dimensions of volume change or do they stay the same?
dimensions can change but the volume remains the same
What is the base unit of volume for the metric system
Liter
What are the most common derived units of the Liter?
milliliter (mL)
deciliter (dL)
microliter (μL)
Define mass
Measures the strength of the resistance of an object when pushed.
How is mass different than weight
Objects would have the same mass on multiple planets but would have a different weight because of the difference in gravity.
What are the most common derived units of the gram?
milligram (mg)
kilogram (kg)
microgram (μg)
What is the modern version of the metric system called?
Identify its abbreviation.
International System of Units
SI
What are the International System of Units (SI) base units
volume: cubic meter, which is the same as 1 L
mass: kilogram
distance: meter
How many L is 1 cubic meter?
1,000 L
Are blood concentration measurements precise?
No, they are approximate.
What is the rule in science and medicine about the final digit in any measured number?
It is never considered correct or accurate.
Define precision
precision is determined based on the results of multiple measurements. something is precise when the returned value is similar multiple times.
Define accuracy
Accuracy is determined by the tool’s ability to give us correct results.
What is the difference between a precise tool and an accurate tool.
Provide example
darts
A tool is precise when it returns the same/similar results repeatedly.
A tool is accurate if it provides the correct answer.
Consider a dart board. If your darts hit the same spot repeatedly, they are precise. If they hit the bullseye, they are accurate.
What is a “standard” when measuring data
a standard is used to determine if a tool is accurate. by measuring something for which you know the value, you can determine if the tool will measure accurately.
Describe how to convert units using the metric railroad
The number of stations you move equals the number of decimal places you move.
As the units move to the right, the decimal places moves to the left and vice versa
as a unit becomes smaller, the number becomes larger and vice versa
Identify the stopping points on the metric railroad from left to right starting with micro
Identify other metric prefixes in common use and their values
think tera and giga
Name the extended metric railroad system in order starting with pico
Define a conversion factor
tells us how two different units relate to one another
What are the four steps to translate any measurement from one unit to another?
literal steps follows to solve the math problem
- identify the original measurement and the unit converting to
- write the conversion factors
- multiply the conversions and cancel units
- do the math, round the answer
What are examples of a unit?
Hours, day, months
What two types of units are used in the metric system?
Base Units and Derived Units
Example of Base Unit
What is the base unit of distance (length, width, height)
meter
What is an example of a derived unit for a meter?
(kilo)meter or (centi)meter
Define Distance
Tells us how far apart two things are
What type of unit is meter and what does it measure?
meter is a base unit that measures distance (length, width, height)
What is the abbreviation for Liter
L
What is the abbreviation for meter?
m
What is the abbreviation for gram?
g
What is the base unit of mass?
gram
express 2.8 dm in mm
280 mm
express a sample conversion
mL to dL
100mL/1dL
and
1dL/100mL
what is a compound unit?
provide example of how it is written
think density
a compound unit is made of two different units
Unit A/Unit B
Unit A per Unit B
define density and express the equation
density is the relationship between mass and the volume of a substance.
density does not change if the volume or mass changes
density = mass/volume
what is specific gravity
write it as an equation
does it have a unit?
closely related to density
specific gravity of a substance = density of the substance/density of water
no unit
provide two examples of when specific gravity is used in medical analysis
blood to determine if someone has enough iron
urine to determine if someone has kidney disease or is dehydrated
how are significant figures determined
we start counting significant figures from the first non zero digit in a number
how do we determine how many significant figures are used to answer an equation
the answer is rounded using the least amount of significant figures determined in the original data set
what numbers are ignored in the significant figure rule
the number 1
any number that converts numbers in the same system (metric to metric or english to english)
exact numbers that cannot be divided or modified
trailing zeros in approximate numbers
what are the freezing and boiling points in celcius
0 freezing
100 boiling
what are the freezing and boiling points fahrenheit
32 degrees freezing
212 degrees boiling
what is the formula for converting Fahrenheit to Celcius
(F-32)/1.8=C
what is the formula for converting celcius to fahrenheit
(Cx1.8)+32=F
how are Kelvin scale temperatures determined?
add 273 to the Celcius temp
