Dr. Daniel Bullock
McEver 03
968-0230
dbullock@mail.atu.edu
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Laboratory Rules
Everyone should have their own lab manuals
every time they come to lab.
Be on time.
Don’t plan to leave early
Food and Drink – no smelly foods
How the Lab Runs
Lecture
Divide into groups of 4
Do the experiment, fill our lab manuals in
PENCIL. YOU MUST BE NEAT
After the lab is COMPLETE Deputy will either
approve or disapprove it.
You will get 5pts for (a) being on time (b)
completing the lab (c) leaving a clean and neat
lab station
If the lab manual is COMPLETE, NEAT,
WRITTEN IN PENCIL, and ACCURATE then
you will take a quiz in another room. (open
book)
GRAPHING
1. You must be neat when you graph.
2. You must use a straight edge to draw lines,
and French Curves to draw curves.
3. Your graph must have: TITLE, AXIS TITLES,
DATA IDENTIFIERS, APPROPRIATE
SCALES
We will talk about this more in a minute.
LAB IS SUPPOSED TO HELP YOUR LECTURE
GRADE!!!! IF YOU DO THE WORK YOU
WILL DO FINE IN THE LAB!
MEASUREMENTS AND ERRORS
Two common types of errors:
1. Random error: due to the precision of
the measuring device and the individual doing
the measurement. These can be minimized by
doing the measurement several times.
2. Systematic error: due to things that are
wrong with the system. Caused by faulty or
uncalibrated equipment. These are easy to fix if
you know about them.
SEE GUN EXAMPLE
Significant Figures
The rule for estimating sig. Figs. Is one-half the
smallest division on the instrument.
0
1
2
cm
How long is the pencil?
It’s somewhere between 1.5cm and 1.6cm
If we follow our rule we could record 1.50, 1.55 or
1.60
How do you count the # of sig figs?
1st locate the first nonzero figure on the right and
count right. 0.0320 would have 3 sig figs.
Math operations with sig figs: # of sig figs is
equal to the # of the lowest sig fig.
52.3
+0.432
52.7
3 sig figs.
How about this example?
4 sig figs.
23.21
X 3.1
71.92
2 sig figs.
So we should record our answer with 2 sig. Figs
resulting in an answer of: 72
When Graphing
Consider the following data: Velocity
7
11
15
THIS IS A BAD GRAPH
19
Time
2
4
6
8
Velocity (m/s)
Velocity vs. Time
40
38
36
34
32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
5
10
15
Time (s)
20
25
30
THIS IS A GOOD GRAPH!
Velocity vs. Time
20
18
16
Velocity (m/s)
14
12
10
8
6
4
2
0
2
3
4
5
Time (s)
6
7
8