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Experimental Design and the Scientific Method

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Presentation on theme: "Experimental Design and the Scientific Method"— Presentation transcript:

1 Experimental Design and the Scientific Method

2 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”?

3 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.

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

5 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

6 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

7 Slope Review Y=mx+b Why do we need slope?
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 is
m = ??? Information from…

8 Lines that are horizontal have a slope of zero
Lines that are horizontal have a slope of zero.  (There is no "rise", creating a zero numerator.) Lines that are vertical have no slope (undefined slope).  (There is no "run", creating a zero denominator.) Lines that are parallel have equal slopes. The graph in the bottom right corner is a misconception. Do not get confused. Zero slope is not the same as having no slope

9 What is Experimental Design?
Laying out a detailed experimental plan in advance of doing the experiment

10 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 Randomize- to make random. To make sure that I have a random sampling from within my sample size Control – to make sure that I have something to compare the results of my experiment to

11 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. Replicate- sample size. How many test subjects I am looking at Block – take care of on the front end of the experiment so I don’ t end up with a bunch of variables that I wasn’t concerned with testing in the first place

12 Parts of Experimental Design
Independent Variable Dependent Variable Hypothesis Control Replication Purpose Experimental Group(s) Control Group Constants

13 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. independent variable(s) Control dependent variable(s) and how you’ll measure it/them replication (sample size)

14 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!

15 Superstitions used for practice with experimental design.
An apple a day keeps the doctor away. Eating chocolate causes zits. Shaving your legs makes the hair grow back more densely. A knife placed under the bed during childbirth will ease the pain of labor. Drinking coffee will stunt a child’s growth. If you swim right after eating, you will get cramps. If you catch a falling leaf on the first day of autumn, you will not catch a cold all winter. If you go outside when your head is wet, you’ll catch a cold. A red ribbon placed on a child who has been sick will keep the illness from returning. A half onion placed under the bed of a sick person will reduce the fever. Feed a cold, starve a fever. Break a mirror and you will have seven years of bad luck. Spit on a new bat before using it for the first time to make it lucky.

16 Warm-up ( ) Without experimental design and the scientific method, would there be valid experiments? What do you think?

17 Outline Objectives Accuracy and precision Scientific method

18 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.

19 Accuracy vs. Precision

20 Accuracy and Precision
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

21 Scientific Method What is it? Is there only one Scientific Method?
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.

22 What is a hypothesis? What is data?
It is an educated guess based on observations and your knowledge of the topic. What is data? It is information gathered during an experiment.

23 Steps Identify the Problem Form a Hypothesis Create an Experiment
What do you want to know or explain? Form a Hypothesis What do you think will happen? Create an Experiment How will you test your hypothesis? Perform the Experiment Follow your procedure to test your hypothesis Analyze the Data Is your data reliable? Does it support your hypothesis?

24 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?

25 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.

26 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

27 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!

28 Outline Objectives Scientific Method Review Peer Review
Experimental design Practice

29 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.

30 Scientific Method… What is it? Steps? Tell me what you know

31 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.

32 Media Sometimes Exaggerates Science
What does this article have to say about the accuracy of reporting in the media? This report shows that the media has accurately reported on the issue of genetic research

33 Peer Review Is the evidence presented appropriate and sufficient to support the claims?? Physical Science Biology Earth Systems Biology II

34 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.

35 Outline Objectives Peer Review Discussion Experimental Design packet

36 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.

37 Discussion

38 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?

39 Outline Objectives Experimental Design packet
Experimental Design discussion

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

41 Graphing Experimental Data
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?

42 What does the slope mean for science?
It is the interaction between the independent and the dependent variables Proportionality 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

43 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. Source:

44

45 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?

46 Outline Objectives Experimental Design Quiz
Ten Unanswered questions in science

47 Objectives To demonstrate knowledge of Experimental Design and Peer Review To explore the top 10 questions about the Earth and develop possible answers.

48 Earth Systems Ten Unanswered Questions

49 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.


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