Electrostatics in Your Home
Laboratory experiments will teach you how to inves tigate physical phenomena scientifically. This
involves taking accurate data, analyzing that data, a nd inferring conclusions from your results. These
skills will be applicable to other technical fields while in high school, college or beyond.
Lab write-ups will generally be collected the Monday following the experiment. When I collect lab
write-ups, I may only collect one from each group. Group size may vary from two to four members.
You will decide as a group whose lab will be turned in. However, everyone must have a complete lab
write-up and they will be stamped on the due date . If you do not have your lab completed on time, or
you are absent the day the lab is due, you will turn in your lab individually once it’s completed and not
receive the group grade. Your grade will be reduced 10% per day late (excused absences excluded if lab
is turned in the day you return to class).
Lab make-ups will occur only twice during the grading period and will be at my discretion. This will
typically occur during the lunch pe riod. If you are not physically presen t for a lab, you may not get the
data from another student in the class to complete the lab. In other words, to get any credit for a lab you
must be present for it execution. With that said, you get no credit for just showing up for the lab. You
must turn in something to get any credit for being there.
You will work in groups of various sizes for the different labs. However, your write-ups should be
written entirely by yourself. I encourage you to discuss the lab, problems you might have had, and
sources of error.
Much of the lab equipment has been recently purchased while some are many years old. Because the
cost of this equipment is high, even though they ma y not look fancy, treat them carefully and put them
back where you found it so as to ensure that it may last many more years.
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LAB REPORT
Lab reports could take the form of one of the following:
1. A simple write-up in which the objective, mate rials, procedures are usually provided and you
conduct the experiment, collect th e data, analyze the data, and answer basic questions provided.
2. A formal write-up where you design a lab activity based on a concept covered. Here only the
objective, planning, variables, and materials need ed, will be written up. No actual experiment or
data will be collected.
3. A formal lab write-up in which you have designed most of the experiment with little, if any
information, provided by the teacher . You will need to follow all of the guidelines below, use the
sample lay-out provided and completely type your reports. Attach handwritten data, drawings
etc. to your formal report.
I. TITLE AND FORMATING
1. Make the title meaningful (eg: “Lab Experiment” is not an acceptable title but “Measuring the
Simple Harmonic Motion of a Pendulum” is.
2. Include the lab number in the title (eg: LAB 11-2)
3. In the right corner of the first page put your name followed by your partner(s) name(s). The
period of your class, and the date the lab was conducted.
4. Every page following the first one needs your name , date lab was conducted, and page number in
the upper right corner.
II. PROBLEM/QUESTION or AIM
1. Define the problem and write it as a general statement.
2. The question is very specific and written so that the answer may be found through a controlled
experiment.
III. HYPOTHESIS
1. Not all experiments will need a hypothesis. If the lab is about learning a particular piece of
equipment, then a hypothesis is not appropriate.
2. When a hypothesis is required relate it directly to the research question.
3. You need to make a prediction.
i. Bad Example: The pressure and volume of a gas are inversely related.
ii. Good Example: For a fixed amount of gas kept at constant temperature its pressure is
inversely proportional to its volume.
4. Explain the hypothesis, at a fundamental level and quantit atively where appropriate.
IV. VARIABLES
You will be conducting experiments to search for cause and effect relationships. The experiment will
be designed so that changes to one item cause something else to vary in a predictable way. These
changing quantities are called variables. A variable is any factor, tra it, or condition that can exist in
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differing amounts or types. An experiment usuall y has three kinds of variables: independent,
dependent, and controlled. The independent variable is the one that is changed by the experimenter.
To ensure a fair test, a good experiment has on ly one independent variable. As the independent
variable is changed you will observe what happens. You will focus your observations on the
dependent variable to see how it responds to the change made to the independent variable. The new
value of the dependent variable is caused by and depends on the value of the independent variable.
For example: If you open a valve to a water pipe (the independent variable), the flow rate (dependent
variable) changes. The number of dependent variables in an experi ment varies, but there is often
more than one.
1. Identify the manipulated variable (independent).
2. Identify measured variable (dep endent) and how it will be measur ed – include both quantitative
and qualitative variables.
3. Identify variables that will be held constant.
Example: the size of the valve opening afore mentioned.
V. MATERIALS
1. Include all materials used (s ize, volume, mass, etc.), and the quantity.
2. Describe any equipment/instrumentation used (ticker tape machine, voltmeter etc.).
3. Do not list equipment fr om a lab sheet if you did not use them.
VI. PROCEDURES
1. Include a picture of you r lab set-up (hand drawn neatly or photo).
2. Your procedure should not be just a list of step s. You should also include an explanation of how
you control the variables and list the calculations /data manipulations that will be done so that
you are sure you’re collecting enough data.
i. The question to ask yourself is: Could someone who had never done this experiment
before, reproduce exactly what you did in th e lab with the instructions written?
ii. Specifically states when and how (units, with what instrument) each variable is
measured.
3. Control of variables. This may seem redundant if you’ve listed va riables in the variable section
(IB only) but you need to explain your choices and how you will control the control variables
here.
4. List all of the possible errors that could occur and then explain how you will address them.
5. Write down any assumptions you are making.
6. Describe what measurements will be taken so that when data is pr ocessed there is sufficient data.
i. List the equations you will be using and stat how each variable will be measured.
ii. Insufficient data may be graphed but ther e may only be two or three points over a
small range.
VII. DATA COLLECTION
1. All data collected with units, significant figures and uncertainties
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i. Record all raw data with precision and presented in an organized way. (Do not
assume that someone will look in the procedures to find out what mass length rope
was used. Record that here too.
ii. Every time you make a measurement – write th at number down even if it’s the same
each time.
iii. Include constants and givens
2. Organize all data and presentation
i. Data is in tables and tables have unambiguous titles and numbers.
ii. Organization is logical, allows for easy interpretation.
Example: Table 1: Resistance of a conductor versus its length .
LENGTH
(m)
POTENTIAL DIFFERENCE
(V)
CURRENT
(A)
RESISTANCE
(R)
0.20 0.630 0.190 3.315
0.40 0.992 0.150 6.613
0.60 1.002 0.101 9.921
0.80 1.090 0.082 13.21
1.00 1.215 0.073 16.70
VIII. DATA ANALYSIS
1. Show all calculations and gra phs in their proper format
2. Results are clearly presented in tables and graphs with units and uncertainties.
3. Calculate averages, lines of best fit and look for other ways to graph data to get more
information.
4. All calculations must be clearly laid out. Show the equations used and unit analysis. Footnote
calculated data shown in data tables with the sample calculations. You should do them on
scratch paper first and then c opy them into your lab report.
5. Briefly head each calculation with what is being solved for.
IX. CONCLUSION
1. Summarize what was done – restat e the purpose of the experiment.
2. Interpret your results and draw a conclusion
i. Describe and explain the theo ry behind your calculations that were performed on the
data.
ii. Give reasonable alternative explanations for the results.
iii. Look for any patterns you can find: look for upward trends/downward trends etc.
3. State whether your hypothesis was supported or not.
4. Compare to literature values and provide % error where appropriate (if there is no literature
value than be sure to discuss the applicable concept/theory).
5. Leave detailed analysis of error out of this paragraph and focus more on what your results do tell
you rather than on why they might not be valid.
6. Error analysis
i. Identification of Errors
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a) Leave out human error, miscalculations, time allotted, lameness o lab
partner(s), etc. Focus on the errors in the lab procedure, equipment, and
management of time. (If you state that the stopwatch was not accurate – show
proof!)
b) What are the limitations, weakness or errors in your procedures?
c) Are there things that came up that you didn’t account for?
d) Id you forget to calibrate the equi pment, or set it up incorrectly?
e) Is your technique poor, cau sing large random errors?
ii. Effect of Errors
a) Was your value too low? What errors contributed to making it low?
b) Was your value too high? What errors contributed to making it too high?
c) Which error, of those listed, was the most insignificant?
d) Are your results reliable, given the errors listed? Justify this.
e) Estimate the magnitude of errors if possible.
X. ENVIRONMENTAL
You will be assessed on the following, even though it is not specifically part of your write-up.
1. All safety rules were adhered to.
2. You and all members of your group remained focused on the task at hand.
3. All instructions were followed accurately.
4. All equipment were treated with care and returned exactly the way they were found.
5. Any equipment damaged during the lab was reported to the instructor.
6. If any, of afore mentioned situa tions are not adhered to, and th e instructor is not able to
determine which group violated protocol (equipment breakage, not returning equipment to
the proper location etc.) will result in the entire class being penalized).
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LAB NOTEBOOK
Your physics lab notebook must be kept in a 3-ring binder. Do not use a spir al notebook or stuff your
labs into a pocket folder. Set-up your lab notebook as follows:
• Title Page
Your name
Period
• Table of Contents
Experiments name – Left side
Lab Number (i.e. LAB 2-1) – Middle
Date conducted – Right side
• Labs in the order performed
• Other
Type all labs
Put a single line through mistakes instead of emptying your ink pen crossing it out.
NO WHITE-OUT.
Keep each lab organized and in a logi cal order (e.g. don’t put materials and
procedure after anal ysis).
Every page for each lab needs a name, date and page number.
Attach all handwritten data to your formal report.
Attach all simulations to your report.
Write your labs in the 3
rd
person rather than the 1
st
person. Example: “The ticker
tape readings were incorrectly recorded.” Is preferred to “Isaac was a klutz and
read the ticker tape wrong.”
Every lab requires a diagram or picture of the set-up. This is part of your procedure.
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