Teacher Guidelines
Developing Experimental Design & Procedures
Timeline:
50-100 minutes for this activity; instruction time to discuss experimental design is not included
in the 50-100 minutes.
Concept Statement
Designing well-controlled experiments is the key to successful science. Identifying the parts of
experimental design helps students to identify the causal agent as well as its effect on one
variable This activity is a fun way for students to demonstrate their prowess at designing
experiments. Students can use things in which they are interested (advertised products) to design
possible experiments.
The purpose of the activity is for students to test the claim that is inherent in the ad they select.
For example, detergent X makes clothes whiter. This can be tested in an experiment.
How to Orchestrate the Lesson
Teaching experimental design: You need to explain the terminology that is critical to
experimental design including independent variable (IV), dependent variable (DV). repeated
trials hypothesis and control. To help students practice identifying these in experiments.
conduct several labs that employ good experimental-design and have students prepare and
experimental design chart on each. Another possibility is to supply the students with various
lab scenarios or abstracts and have them practice finding experimental design components m
the scenario.
Group size: Students should work in groups of two or three.
Finding magazine ads: Finding magazine ads can be done in two ways.
1. Find advertisements for the students and clip these before the class.
2. Have students locate their own ads The latter is somewhat more advanced as students need to
identify an ad about which they can design a well-controlled experiment Good quality ads claim
that one product does some measurable thing better than other similar products. Toothpaste,
detergent, gasoline and medication are usually good examples.
Developing the experimental design: Once a student group selects an ad, they need to design
an experiment that tests the claim the ad expresses. The experimental design can be
expressed in the chart format provided or in a narrative format as you feel necessary.
Adapted from AVID HS Science Content, Helix HS
Components of Good Procedure Writing
For scientists, it is critical for other researchers to replicate
experimental studies to verify the results Being able to replicate the
results of an investigation allows us to strengthen the conclusions
made in the first study. Precision is vital in explaining how to set up the
groups, how to control the constants and how the measure the
variables.
The following is a list of essentials for writing procedures. Be very
specific. When in doubt about how much to include about your
methods, include more. It is better to remove information when you
find out it is not needed than to have to stop a procedure because it is
unclear what to do next
1. Use a numbered list of steps.
2. Organize the steps into small discrete directions in the order you would do them in lab.
3. Avoid using pronouns.
4. Use commands.
5. Explain how you selected your sample of organisms or materials.
6. Tell the reader to measure and record data when it is appropriate.
7. Explain what data to record and how to measure this data.
8. Refer to measurements using only the metric system.
9. Eliminate extraneous information.
10. Sketch and label the experimental set-up. Refer to sketch in your procedure. If you need
multiple sketches, number them starting with 1. Refer to each sketch by number in the
procedure.
11. Include all steps. No matter how small the step seems, it may be the critical step for a
researcher to replicate your procedure.
12. Explain how to control all variables except the experimental, independent variable.
13. Refer to all equipment listed in the materials section.
14. Tell the experimenter when it is necessary to repeat one or more steps in the
procedure.
Adapted from AVID HS Science Content, Helix HS
Magazine Ad Experimental Design
Experimental design is the way in which cause-effect relationships are discovered in science. To show
what you know about experimental design, you will design an experiment to test the claims in a
magazine advertisement
Procedure:
1. Select a magazine ad from the designated stack of magazine ads.
2. Neatly cut-out the advertisement.
3. Design a valid experiment that focuses on what the magazine ad is
claiming. The experiment must be within school regulations. If your
experiment were a movie it must be rated G or PG.
4. Create an Experimental Design Chart showing the design of your valid experiment. This should
be neatly written using markers.
5. Write the steps for the procedure to complete this experiment. This should be a complete list of
steps. Things to consider for your procedure might include:
 how much of the product to apply,
 how to choose the participants,
 how to measure the responses/variables,
 how many times to conduct experiment,
 what conditions must be kept the same (constants) and how to do this, what types of
experimental groups are used. etc.
6. Peer Review your procedure with another group. Redraft your procedure based on the all
revisions suggested.
7. Attach the ad and the procedure to the front of your poster. See below.
Group Member Names
Attach Ad
here
Attach or Write
Procedure Here
Attach
ExD here
Helpful Hints: All great experiments need to have:

Lots of repeated trials (assume you have an unlimited money supply)

A minimum of three different independent variable groups.

A control group that is well defined.

Legitimate constants - equipment / environment will not count unless you are specific and it
really relates. Remember that constants are all the factors that must remain the same in an
experiment. They are controlled variables. For example, when growing plants under different
color light, it is important to keep the amount of light and water that all plants receive constant. If
you change this for each plant or groups of plants, these factors may affect the results. Plants
with more light will grow taller, no matter if the color of the light is blue or red.

A testable hypothesis
 A detailed, repeatable procedure
Adapted from AVID HS Science Content, Helix HS
Committee Review of Experimental Design.
Scientific journals often use committee review to accept or reject
papers that are submitted for publication. The first step is forming a
committee. Your committee should be composed of 4 people who
understand scientific design and are willing to provide your with
constructive criticism about your research. Your committee should be a
powerful screen for the quality of your experiment so that flaws can be
repaired and kinks can be worked out BEFORE it is reviewed by your
teacher.
In order to help your committee be critical (in a tactful manner), we, the publishers, have provided a
checklist of crucial aspects for your experimental design. Your committee is there to help you prepare
your best design by examining your work with a fine tooth comb. They should ask you tough questions
about your design. You need to develop responses to these questions and modify your experimental
design accordingly. No detail is too small to overlook!
Experimental Design (ExD)
 Needs to be only section on page
 Needs “ExD” written at top, center
Title section
 Accurately describes experiment
 Relates IV &DV
 Is fewer than 15 words
 Includes all key words (for key word search)
 Would be improved as a question
 Includes scientific name of organism (underlined; capitalize genus)
Hypothesis section
 States reasonable relationship about IV & DV
 Relationship is based on research (not out of the blue)
 States condition and/or effect
 Sets up designed experiment
 Needs to eliminate personal pronouns
Independent Variable (IV)
 Quantitatively measurable or easily categorized
 Can be manipulated by researcher
Experimental Groups
 Well-described experimental groups
 Experimental groups are feasible for researcher to create
 3 or more experimental groups
 States reasonable number of repeated trials for experiment
 Minimum of 10 repeated trials
 Control group is included
Dependent Variable (DV)
 Quantitatively measurable
Adapted from AVID HS Science Content, Helix HS

Is a result of IV
Controlled Experiment (Constants & Control)
 Lists all necessary constants
 Specifies quantities of environmental constants (ex. amount of sunlight)
 Experimental groups are controllable
Materials Section
 Lists all required materials
 Lists quantity of materials
 Lists equipment required
 Is comprehensive
 Researcher knows how to obtain materials and equipment
 Researcher will be able to obtain materials and equipment
Methods Section
 Numbered list of steps
 Uses commands
 Limited to steps of experiment (not do calculations)
 Is comprehensive and repeatable
 Steps are short & clear enough to follow easily
 State how to collect exact measurements (including how to measure height)
 Explains how to set-up or build equipment
 Has diagram(s) to show equipment set-up
Comments: (Required by each committee member)
It is the recommendation of this committee that this experimental design is: (choose one)
 Exceptional - minor adjustments required; little concern about project design
 Skillful - some adjustments required; needs revision but minimal concern
 Adequate - many adjustments required; concerned about project design
 Poor - major modifications required; significant concern about project design
 Unacceptable - major alterations required; significant concern about project design
The revisions that need to occur for reconsideration are:
1. _____________________________________
6. ___________________________________
2. _____________________________________
7. ___________________________________
3. _____________________________________
8. ___________________________________
Adapted from AVID HS Science Content, Helix HS
4. _____________________________________
9. ___________________________________
5. _____________________________________
10. ___________________________________
Signed: ________________________________
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Adapted from AVID HS Science Content, Helix HS
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