Measurement
Measurement
Metric units
• The fundamental units :
• length is the meter (m)
• Mass is the gram (g)
• Volume is the liter (l)
• Temperature is degree Kelvin (°K)
– but Celsius (°C) is more commonly used
Measurement
Metric units
• The metric system is based on the number 10
and therefore a decimal system
•
Prefixes precede the root or main word (gram, liter, meter).
•
The following prefixes are commonly used in science:
Measurement
Metric units
• Examples:
• A millimeter is about how
thick as a toenail.
• A centimeter is about as
thick as a dime.
• A kilometer is a little more
than half of a mile.
Measurement
Conversions
• The base represents gram, liter and meter.
------------------●-------●-------●------●--------●--------●--------------●-----------●---------●-----------●-------●--------●-------●------------*--Prefix: Mega
Kilo
Hecto Deca
Basic Unit
Deci
Centi
Milli
Micro
Abbrev:
M
k
h
dc
m, l, g
d
c
m
mc or μ
Measurement
Conversions
• Moving to the RIGHT ------increase
• Moving to the LEFT -------decrease
Measurement
Conversions
• Hint – we are referring to the exponent
associated with 10 when we “count”
places to move the decimal
• We are NOT counting actual words listed
on the chart
For example
• if you have 80 hl
and you want to
convert to cl
then you must
move 4 spaces
to the right.
• So you move
your decimal
point 4 spaces to
the right.
• Your answer is
800000 cl
For example
• if you have 5mg and
you want to convert to
g then you must
move 3 spaces to the
left.
• So you move your
decimal point 3
spaces to the left.
• Your answer is
0.005g
Measurement
Length
• The basic metric unit of length is the
meter (m).
• DIFFERENCES BETWEEN:
– English units
– Metric units
Measurement
Length
Volume
• When a figure has three dimensions
(length, width, and height) we can find its volume.
• In the metric system volume can be expressed
in terms of liters or cubic centimeters
(cm3 or cc)
Volume
• The meniscus is the curved interface
between the water and air.
• This is due to the surface tension and
adhesive forces of water as it interacts
with its container.
A: The bottom of a concave meniscus.
B: The top of a convex meniscus.
Volume
• In a laboratory you would work with
• pipettes: pipette pump or filling device is
used to draw and dispense fluids
Volume
•
•
•
•
In a laboratory you would work with
Graduated cylinders
Erlenmeyer flasks
Beakers
Mass
• Mass is a measurement of the amount of
matter in an object. It is determined by the
molecular structure of the object.
• Not to be confused with…………..
Mass
• Weight is a measure of the gravitational
pull on an object. It is not the same as
mass.
Mass
• In a laboratory you would work with
Triple beam balance / Electronic scale
Scientific Notation
• Scientific notation uses powers of 10 so
very large or small numbers can be
expressed concisely.
Scientific Notation
• The number we use as the base for this
system is 10. The exponent is the power
of the number and is applied to the base.
For example
• Write the following large number using Scientific
Notation : 146,000,000,000.
– Step 1 :place the decimal after the first digit and drop
all the zeros.
1.46
000,000,000_
- Step 2: count the number of places from the decimal
to the end of the number. There are 11 places after
the decimal point; therefore the exponent is 11.
1.46 X 1011
For example
0.00000123
– Step 1: with small numbers you count from the
decimal the number of zeroes until you reach the first
non-zero number
0.00000123 = 1.23 X10-6
Graphing Data
Line graphs have both X axis and Y axis.
Each X and Y axis is subdivided into
uniform intervals.