Experimental Design and the Scientific Method

Warm-up (8-27-14)

• Write down what you think experimental design means

• Why do you think experimental design is important?

• Can you perform an experiment without thinking of “experimental design”?

Warm-up (8-28-14)

• What are the steps of the scientific method?• Why does slope matter in science?• Give an example of a poorly designed

experiment.

Outline

• Objectives• Why do I care?• Slope Review• What is Experimental Design?• Purpose• Scientific Method• Steps

Objectives

• Explain the purpose of experimental design and why it is important

• Determine the difference between accuracy and precision

• Explain the importance of the scientific method and why peer review is significant

Why Do I Care?

• Experimental design determines the validity of the results presented

• Determines whether or not you can trust the experiment

• Scientific Method is the basis for all scientific thinking and questioning

Slope Review

• Y=mx+b– What do these random letters mean??

• Why do we need slope?– The slope of a line is a rate of change and is

represented by m. • • When a line passes through the points (x1, y1)

and (x2, y2), the slope ism = ???

What is Experimental Design?

What is the PURPOSE of Experimental Design?

• Randomize– Even out effects we cannot control – Ensure equal chance to all possibilities

• Control– Make sure we only get results for what we want

What is the PURPOSE of Experimental Design?

• Replicate– Get as many replicates (repeats) as possible.– Results for a single subject might not be accurate. (No

one is perfect on the first try all of the time.)• Block– Get rid of things we don’t want to study and that we

can’t control• Best Experiments Are??• The best experiments are usually randomized,

comparative, double-blind, and placebo-controlled.

Parts of Experimental Design

• Independent Variable• Dependent Variable• Hypothesis• Control• Replication• Purpose• Experimental Group(s)• Control Group• Constants

Let’s Try It!

Experimental Design Practice (Remember our check list!)• What do we need to include / What questions

do we have to answer?Superstitions• If you blow out all the candles on your

birthday cake with the first puff you will get your wish.

You Try It!

• Complete the activity with your table groups. I will number your tables!

• Make sure that you are each writing down the answers on your own paper.

• You will need these examples as a reference!

• Superstitions used for practice with experimental design.1. An apple a day keeps the doctor away.2. Eating chocolate causes zits.3. Shaving your legs makes the hair grow back more densely.4. A knife placed under the bed during childbirth will ease the pain of

labor.5. Drinking coffee will stunt a child’s growth.6. If you swim right after eating, you will get cramps.7. If you catch a falling leaf on the first day of autumn, you will not catch

a cold all winter.8. If you go outside when your head is wet, you’ll catch a cold. 9. A red ribbon placed on a child who has been sick will keep the illness

from returning.10. A half onion placed under the bed of a sick person will reduce the

fever.11. Feed a cold, starve a fever.12. Break a mirror and you will have seven years of bad luck.13. Spit on a new bat before using it for the first time to make it lucky.

Warm-up (8-29-14)

• Without experimental design and the scientific method, would there be valid experiments? What do you think?

• https://www.youtube.com/watch?v=eA86dYxrg4Q

Outline

• Objectives• Accuracy and precision• Scientific method

Objectives

• Determine the difference between accuracy and precision

• Explain the importance of the scientific method and why peer review is significant

• Determine the importance of peer review and practice using peer review to evaluate the work of scientists.

Accuracy vs. Precision

Accuracy and Precision

• Accuracy:– the degree to which the result of a measurement,

calculation, or specification conforms to the correct value or a standard.

• Precision:– Related to reproducibility and repeatability– Exactness– Related to those other points / values around it

Scientific Method

• What is it?– It is a process that is used to find answers to questions

about the world around us.• Is there only one Scientific Method?– No, there are several versions of the scientific method.

Some versions have more steps, while others may have only a few. However, they all begin with the identification of a problem or a question to be answered based on observations of the world around us and provide an organized method for conducting and analyzing an experiment.

• What is a hypothesis?– It is an educated guess based on observations and

your knowledge of the topic.• What is data?– It is information gathered during an experiment.

Steps1. Identify the Problem

What do you want to know or explain?

2. Form a HypothesisWhat do you think will happen?

3. Create an ExperimentHow will you test your hypothesis?

4. Perform the ExperimentFollow your procedure to test your hypothesis

5. Analyze the DataIs your data reliable? Does it support your hypothesis?

Simpson’s Experiments

• Analyze the Simpson’s Experiments.• Keep in mind both experimental design and

the scientific method. For each one, answer the four questions AS WELL AS these three prompts…– What is the Problem?– What is the Hypothesis?– What is the Data?

If your data is inaccurate or flawed…

• Modify your experiment– Rewrite your procedure to address the flaws in the

original experiment

If your data is NOT inaccurate or flawed…

• Communicate the Results– Write a conclusion that summarizes the important parts of your

experiment and results.– Explain why you got the results that you did and what those

results mean.

Ethical Traditions of Science

• Value peer review • Truthful reporting of methods and outcomes• Making work public • Sharing a lens of professional skepticism when

reviewing the work of others

Warm up (9-2-14)

• Come in, grab a warm-up sheet from the front table, find your seat and get started answering your warm up..

• Design an experiment about the human body’s response to exercise. – Please be specific and detailed. Remember the

parts of experimental design in your answer!

Outline

• Objectives• Scientific Method Review• Peer Review• Experimental design Practice

Objectives

• Determine the importance of peer review and practice using peer review to evaluate the work of scientists.

• Practice experimental design and evaluating experiments using the guidelines established for good experimental design.

Scientific Method…

• What is it?• Steps?• Tell me what you know

Peer Review a Scientific Article

• Peer review methods are employed to maintain standards of quality, improve performance, and provide credibility.

• Often used to determine an academic paper's suitability for publication.

• http://science.howstuffworks.com/innovation/scientific-experiments/scientific-peer-review.htm

Media Sometimes Exaggerates Science

• http://www.cmaj.ca/content/170/9/1399.full.pdf&embedded=true

• What does this article have to say about the accuracy of reporting in the media?

Peer Review

• Is the evidence presented appropriate and sufficient to support the claims??

• Physical Science• http://www.sciencedaily.com/releases/2010/08/100802101813.htm

• Biology• http://www.thehindu.com/opinion/lead/lead-article-ebolas-reemergence-a-wakeu

p-call/article6357471.ece

• Earth Systems• http://leisureguy.wordpress.com/2007/09/04/the-scientific-consensus-on-global-warming/

• Biology II• http://www.sciencedaily.com/releases/2014/08/140828142752.htm

Warm up (9-3-14)

• Explain why experimental design is important to an experiment.

• Describe how the scientific method, experimental design, and peer review are all connected.

Outline

• Objectives• Peer Review Discussion• Experimental Design packet

Objectives

• Practice using peer review to evaluate the work of scientists.

• Practice experimental design and evaluating experiments using the guidelines established for good experimental design.

Discussion

Warm up (9-4-14)

• What does peer review have to do with science?

• What is the significance of making sure that everyone is using good experimental design techniques?

• Do you need to use experimental design in this class? Why?

Outline

• Objectives• Experimental Design packet• Experimental Design discussion

Objectives

• Practice experimental design and evaluating experiments using the guidelines established for good experimental design.

Graphing Experimental Data

• http://gbhsweb.glenbrook225.org/GBS/Science/chem/chem163/projects/factory/quiz.htm

• Graph the results from the table• Be sure to label the axis and title your graph

(keep in mind independent and dependent variables)

• Use appropriate scales• How would I find the slope of this data?

What does the slope mean for science?• It is the interaction between the independent and

the dependent variablesProportionality• two variables are proportional if a change in one is

always accompanied by a change in the other, and if the changes are always related by use of a constant.

• Directly proportional: y=cx• Inversely proportional: y=c/x

• Inversely Proportional: when one value decreases at the same rate that the other increases.

• Directly proportional: as one amount increases, another amount increases at the same rate.

Warm-up (9-5-14)

• If you were planning on conducting an experiment and you wanted to make sure that you got funding… What are the steps you should be sure to follow?

• What are the purposes of experimental design?

Outline

• Objectives• Experimental Design Quiz• Ten Unanswered questions in science

Objectives

• To demonstrate knowledge of Experimental Design and Peer Review

• To explore the top 10 questions about the Earth and develop possible answers.

Earth Systems

• Ten Unanswered Questions• http://www.livescience.com/4849-top-10-que

stions-earth.html

Quiz!

• For this quiz…• No talking• You may use your notes, and only your notes• When you finish make sure that you are

working on something to keep yourselves quiet.

• If you talk after you have turned in your quiz, points may be taken off.