Calibration,
Temperature &
Percent Error
What is Calibration?
Calibration of any measuring device is:
distance between two closest lines
(Not distance between two closest #’s!)
Not all
graduated
cylinders
calibrated
same way
Large graduated cylinder:
? capacity
? calibration
1000 ml
10 ml
? calibration
1 ml
? calibration
1 ml
? calibration
0.2 ml
Here are some other pieces of lab
equipment.
Can you figure the calibration of
each?
meter stick: two closest lines
are 1 millimeter apart
? calibration
25 ml
This is a
quadruple
beam
balance
What’s the calibration?
0.01 gram
This is a buret
? calibration
0.1 ml
Note: unlike graduated cylinder, numbers go
down, so you read downwards
Temperature
Scales
Scientifically speaking …
The definition of temperature:
Temperature is measure of average
kinetic energy of particles in system
World’s Record Cold
Temperatures
˚F
˚C
7/21/1983
2/7/1892
2/6/1933
1/9/1954
2/3/1947
1/23/1971
–129
–94
–90
–87
–81
–80
–89
–70
–68
–66
–63
–62
1/20/1954
–70
–56.5
Date
World (Antarctica): Vostok II
Verkhoyansk, Russia (Siberia)
Asia: Oimekon, Russia
Greenland: Northice
No A: Snag, Yukon, Canada
US: Prospect Creek, Alaska
US: (other than AK)
Rogers Pass, Mont.
Conversion formulas
How can we convert from one temperature scale
to another?
K = °C + 273
273.15)
(more precisely
°C = K – 273
[F = (9/5 °C) + 32]
Errors are inevitable
and need to be dealt
with …
Percent Error
Ratio of error to accepted value
% error =
Error
accepted value
x
100%
Error
measuredaccepted
value – accepted value x100%
value
absolute value: always positive
Data table
Students asked to find density of sucrose
[Sucrose has density of 1.59 g/cm3]
Student A
(g/cm3)
Student B
(g/cm3)
Student C
(g/cm3)
Trial 1
1.54
1.40
1.70
Trial 2
1.60
1.68
1.69
Trial 3
1.57
1.45
1.71
Let’s calculate the error
Student A
(g/cm3)
Student B
(g/cm3)
Student C
(g/cm3)
Trial 1
0.05
0.19
0.11
Trial 2
0.01
0.09
0.10
Trial 3
0.02
0.14
0.12
Remember, error is always positive number
Now let’s calculate % error
Student A
% error
Student B
error
Student C
error
Trial 1
3.14
11.9
6.9
Trial 2
0.63
5.7
6.3
Trial 3
1.26
8.8
7.5
Advantage of % Error
• easier to compare data,
especially if comparing data
from different trials