Experimental design

Bubbles!

Title

• Your choice

• It should have something to do with your experiment

Problem or purpose

• What are your trying to find out?

Something to do with the bubbles?

Brands?

Things added to the solutions?

Materials

• A complete list of materials needed to do the experiment

Procedure• A detailed list of exactly what you did.

Procedure cont.

Data• Chart the

findings • Record

observations as the experiment is happening.

• observations

1

floated, started to break down at 2 min

2

3 4

Cost of soap

• Ajax:  $1.87 – 30 oz

• Dawn:  $2.83 – 24 oz

• Great Value:  $1.97 – 24 oz

• Palmolive $2.64 – 25 oz

• Gain $1.97 – 30 oz

Data Analysis

• Organize the data: graphs , charts, ranges, mean, median, mode etc.

Conclusion• How do the results relate to the original

problem?

• What were some possible errors in your procedure? Timing? Temp? Number of repetitions? Amount of water? Control? Was there only one variable?

• How could this experiment be improved?

• Extensions: How could this info be useful in real life? What might it mean? Does it make you come up with another hypothesis?

Share your Results

• Turn in your formal write up.

LAB REPORT FORMAT

• Note: all lab reports are to utilize this format (discrete sections, labeled as below, are mandatory). Reports are to use formal language; avoid using the words ‘we’, ‘I’, ‘us, ‘our’, etc. The report should have a title, your names, the date, and your class period. Conserve paper! Use both sides and eliminate unnecessary extra spacing.

INTRODUCTION• I. Describe the general rationale for your

investigation (Why is this being done? Why is this an important study? What can we learn or apply from this?).

• -Provide all appropriate background information for reader.

• -Clearly state the purpose of your investigation.

• -State hypothesis or hypotheses (null and alternative are often appropriate

Materials and Methods (Procedure)

• II. -List the materials used in your investigation.

-List (and describe, if appropriate) the procedures employed. This should be in list form, NOT a paragraph. Do not describe standard techniques such as massing or transferring fluids.

Remember that your goal is to provide sufficient information so that your investigation: 1. can be readily reproduced 2. can be evaluated for errors, limitations, etc. so that any conclusions can be assessed for believability (confidence).

• -If the procedure was provided prior to your investigation, you may simply attach it to your report. It is important to describe any changes which may have occurred from this protocol.

III. RESULTS

•   -Present all data in clear and concise forms (at times, graph paper or other materials may be provided for this purpose). If calculations are involved, show all work or work through one problem to illustrate.

• -Make certain that all charts, graphs, tables, etc. are clearly titled and labeled.

• -Highlight trends or significant results for the reader (do not repeat all data in prose form).

• -This section may also include a statistical analysis of your data.

IV. CONCLUSIONS

-Evaluate data in light of your hypothesis. Be careful with your choice of words; avoid the word prove!

• -Interpret and analyze your data for the reader. Offer possible explanations or reasons for your obtained data.

• -In light of your materials and procedure, evaluate your experiment. Describe the sources of possible error or the limitations of your materials or procedure. Suggest means of reducing these errors. Suggest improvements and include suggestions for further possible studies (how could this study be extended to provide relevant information?).

score topic Advanced (5) Proficient (3) Needs Improvement (1)

Question Question is narrowly focused and suggests how an answer might be investigated. It is answerable.

Question is answerable but not narrowly focused.

Question is too broad and not practically investigated.

Identificationof Variables

Correctly identifies specific, measurable independent and dependent variables.

Identifies variable being tested & variable being measured. .

• Variables and constantssignificantly incomplete &/orinaccurate.

Hypothesis Hypothesis is testable and clearlystated in “If… then…” format.Specifically predicts relationshipbetween dependent and independent variables.

Hypothesis is clearly stated. Itpredicts the influence of one variable on another.

Hypothesis is poorly stated anddoesn’t directly mention thevariables.

Materials Complete, detailed list of materials (size, conc., quantity) presented in vertical list format

Most materials are listed and appropriate.

Materials quite incomplete or inappropriate for experiment.

Procedure Accurately tests the hypothesis Attempts to test hypothesis Does not address hypothesis.

Conducts or analyzes at least 3 trials. Multiple trials attempted or need is recognized.

Single trial, poor understanding of use of multiple trials.

Procedure is in vertical listformat, accurate, complete, easy to-follow, and reproducible byanother person. Includesdiagrams to clarify procedures

Step-by-step procedure, generallyComplete. Minor errors/omissions make it difficult tofollow or not always repeatable

• Procedure difficult to follow Major omissions or errors.

• Includes all appropriate safety concerns. Includes critical safety concerns

Safety concerns trivial or inadequately addressed.

DataCollection &Presentation

Data table contains accurate,precise raw data & summary datareported in correct SI units withdescriptive title.

Data table with accurate data,most units labeled or implied.Minor errors. Title absent ortrivial.

Data table inaccurate, confusing,and/or incomplete. Missing units.

Data summarized in well organized,easy-to-read graph &/or figures. Descriptive title, appropriate labeling, keys, etc.

• Data displayed in well organized easy to read graph &/or figures.Descriptive title, minor errors in use of units and labeling.

• Graph/figures presented in aconfusing and/or sloppy fashion.

Data summarized in a clear,concise, logical manner Patterns identified & described,but no conclusions drawn.

Reasonable, but somewhatunclear summary of data.Patterns in data not clearlyidentified.

• Summary is unclear and illogical.Patterns in data not identified.

Conclusion Scientifically valid, logicalconclusion, well supported by thedata collected. Clearly addresses problem and stated hypothesis.

• Scientifically valid, logicalconclusion, supported by datacollected. Attempts to addressproblem and stated hypothesis.

Conclusion is incomplete orillogical. Does not address theproblem and hypothesis.

Sources of error identified andexplained. Appropriate recommendations made to eliminate errors.

• Sources of error identified Weak/trivial attempt to identifysources of error.

Student generates specificquestions for future study

Student makes attempt togenerate questions for futurestudy.

Student makes incomplete orinappropriate attempt to extend or apply knowledge.