Please complete all questions

11

Science is one way of explaining natural phenomena. The process of science is based on a specific process called the scientific method (see Concepts of Biology, Section 1.2). The steps of the scientific method are:

1. Make observations.

2. Ask a question.

3. Formulate a falsifiable hypothesis that is a proposed answer to the question.

4. Design and carry out a test of the hypothesis (this might include running experiments).

5. Analyze the results of the test.

6. Evaluate the validity of the hypothesis.

   1. If the hypothesis is supported by the data, then base new observations and questions on this new knowledge.

   2. If the hypothesis is not supported by the data, then formulate a new hypothesis to answer the question and test again.

7. Report the results of the study.

In this lab, we will apply the scientific method using a simple but effective test of reaction time and we will evaluate a published scientific study that employs the scientific method.

Upon successful completion of this lab, you should be able to:

• Explain the process of the scientific method.

• Identify the steps of scientific method from a novel example.

• Demonstrate the ability to generate hypotheses and test them experimentally.

• Recall the characteristics of a good hypothesis

• Distinguish between hypothesis and theory

• Identify the dependent, independent, controlled (standardized) and confounding variables in experiments.

• Identify the control group and experimental group in an experiment. Note the difference between a control group and a controlled variable.

• Demonstrate the ability to draw an appropriate graph using data from a new scenario.

• Interpret graphs of data.

• Identify variables from a graph.

• Distinguish between continuous data and categorical (discontinuous) data.

• Compare and contrast scientific journal articles and magazine articles.

• Explain peer review.

• Recall the format of a scientific journal article (abstract, introduction, materials and methods, results and including the information found in each section:

  • The question or problem

  • The hypothesis

  • The experimental design

  • The data and outcomes of the experiment

  • Whether or not the hypothesis was supported

• Read: Concepts of Biology (our textbook): The Nature of Science—Paragraphs 1-3 (pages 17-18); Hypothesis Testing (pages 19-20) and Reporting Scientific Work (page 23).

• Watch: Video—The Scientific Method (https://www.youtube.com/watch?v=yi0hwFDQTSQ)

• A simple device to detect concussions (http://well.blogs.nytimes.com/2013/08/14/a-simple-device-to-detect-concussions/)

• Watch: Video—How to Measure Your Reaction Time (https://www.youtube.com/watch?v=3vGwbB7TTuM)

• Participants: You and at least one other person in your household (more is better)

• Straight stick that is at least 12 inches or 30 cm long (longer is better). Exampes are a wooden or plastic ruler, or a section of dowel rod, or a broom handle, or a golf club.

• Ruler with centimeter (cm) marks. If you don’t have a ruler, you can make a ruler by doing following:

  • Do an internet search for a printable cm-ruler. The print this ruler (make sure your printer is set to print at 100% or full scale).

  • Download the “Make a 28 Centimeter Ruler” powerpoint presentation from our course Canvas site and follow the directions in that presentation.

1. Taking turns, have each participant act as a reaction time test subject using the methods shown in Figures a and b of the “A simple device to detect concussions” New York Times article and the “How to Measure Your Reaction Time” video.

   1. The test subject sits in a chair with the elbow and wrist of the dominant forearm (right arm for a right-handed person, left arm for a left-handed person) resting on a table and the hand ready to grasp the drop stick measurement device.

   2. The examiner stands in front of the test subject, holding the end of the stick such that the other end is suspended just above the grasp of the test subject.

   3. After a delay of 2-5 seconds, the examiner releases the drop stick measuring device.

   4. Upon seeing the release of the drop stick measuring device, the test subject grabs the device as quickly as possible.

   5. The distance the drop stick is measured in centimeters.

2. Each participant should practice catching the stick at least twice.

3. Each participant should then catch the stick two times. The drop distance for each catch should be measured (in cm). These measurements should recorded in Table 1 (below).

4. For each participant, calculate the average drop distance by adding the two Drop Distances together then dividing by 2 catch attempts: (Drop Distance 1 + Drop Distance 2)/2. For each participant, estimate the Average Reaction Time (in seconds) using the formula:

(You can also use the online reaction time calculator: https://jscalc.io/calc/RWnbOuW9IaxSGtfR)

Table 1. Baseline Reaction Data

In this activity, you will design and carry out the scientific method to address a question of whether or not environmental factor affects human reaction time.

Here are some concepts that are important in the scientific method and experimental design:

• Hypothesis: An informed potential answer to a scientific question. Scientific hypotheses are testable and falsifiable, are statements (not questions) and are always worded in direct, concrete ways. For example: Playing classical music to babies increases their intelligence quotients (IQs) when they are in elementary schools.

• Variables: Factors that vary. Playing classical music to babies is not a variable. Playing classical music to some babies and not playing classical music to other babies is a variable.

• Independent Variable (also called the Manipulated Variable): A variable that isn’t affected by other variables in the scientific study. Playing classical music to some babies and not playing classical music to other babies is the independent variable that would address the hypothesis above. Whether or not babies listen to classical music is independent (not affected by) the elementary school IQs when those babies get older.

• Dependent Variable: A variable the is hypothesized to be dependent on the independent variable. In the hypothesis above, elementary school IQ is the dependent variable because it is hypothesized to depend on whether or not they listened to classical music when they were babies.

• Experimental group (also called the Treatment group): The group of test subjects that receive the treatment that is hypothesized to have an effect. For the hypothesis above, the experimental group would be the babies that listen to classical music.

• Control group: The group of test subjects that do not receive the treatment that is hypothesized to have an effect. For the hypothesis above, the Control group would be babies who are not exposed to classical music.

• Controlled Variables: Variables (factors that can vary) but are controlled by the experimenters. For example to test the above hypothesis, the experimenters may include only babies that are 6 to 9 months old and may select families from specific socioeconomic groups who live in defined regions.

• Confounding Variables: These are variables that the experimenters cannot control and that may influence the outcomes of the study. For the hypothesis above, a confounding variable might be whether or not parents listen to classical music at other times (when they’re not participating in the study).

• Sample Size: The number of test subjects involved in the study. In general, the larger the sample size, the less influence outlier data will have on the average results and the more power the study will have to detect differences in the dependent variable between the experimental group and the control group.

Some potential variables that can be manipulated:

Sitting vs Standing vs Lying down

Reading something on a smart phone screen 

Alteration of hand muscle tone (opening/closing fingers multiple times prior to reaction test)

Physical exertion versus sedentary

Caffeine consumption

Dominant hand vs Nondominant hand

Non-dizzy vs Dizzy

1. Choose one of the above variables to test in relation to reaction time. What do you know about that variable, in relation to reaction time, that forms your background observations/research/experiences?

2. What is your research question?

3. What is your falsifiable hypothesis? Remember that a hypothesis is a concrete statement that offers a testable explanation or answer to the research question.

4. Describe your experimental methods:

   1. What is your Independent Variable?

   2. What is your Dependent Variable?

   3. What is your Experimental Group?

   4. What is your Control Group?

   5. What are variables that you will try to control (Controlled Variables)?

   6. What are some Confounding Variables?

1. Carry out your experiment and record the results in Table 2.

Table 2. Reaction Data Under Manipulated (Experimental) Conditions

• Read: The “Graphing Data” section of Principles of Biology (click here)

by Bartee, L., Shriner, W., and Creech, C., licensed under a Creative Commons Attribution 4.0 International License.

• • Be sure to read the entire “Graphing Data” section, including the Example.

1. Use the following graph paper to draw a graph that displays your data (from Table 2).*. Present your graph in a way that shows trends in a way that helps to evaluate your hypothesis. Here are some things to consider when preparing your graph:

   1. What is your independent variable? What is your dependent variable? Where are you going to display these variables on your graph.

   2. Is it better to graph Drop Distance or Reaction Time? Why?

   3. What type of graph are you going to draw (line graph, bar graph, scatter plot)?

   4. Are you going to plot all of the data or the averages? Why? [What does the “Graphing Data” reading say about this?]

   5. What scale will you use for each axis so that you make the most effective use of the graph paper space that is available?

   6. How will you clearly differentiate between the data of the experimental group from the data of the control group?

   7. What are your axis labels (including the units of measurement)?

   8. What will the descriptive title/caption be for your graph?

*If you do not have access to a printer and are completing this Lab Module electronically, then please draw your graph on a separate sheet of paper. The take a photo of this graph and upload it along with your completed electronic Lab Module document.

The New York Times article (“A Simple Device to Detect Concussions”), that you read as part of the Preliminary Activities for the lab, was a summary of an actual scientific study that was performed by a team of researchers led by James Eckner. The Eckner team published their study in a peer-reviewed scientific journal, the British Journal of Sports Medicine. In Activity 4, you will read the Eckner article and compare it to the New York Times newspaper summary.

• Read: Effect of Sport Related Concussion on Clinically Measured Simple Reaction Time (click here) by Eckner, J.T., Kutcher, J.S., Broglio, S.P., and Richardson, J.K. (2014). British Journal of Sports Medicine 48(2). doi: 10.1136/bjsports-2012-091579

1. In the Eckner et al. (2014) study, what was the overall scientific question (scientific method step 2)?

1. In the Eckner et al. study, what was the hypothesis (scientific method step 3)?

1. In the Eckner et al. study, what was the dependent variable?

1. In the Eckner et al. study, what was the independent variable?

1. In the Eckner et al. study, what was the experimental group? What was the control group?

1. In the Eckner et al. study, what was the sample size for each treatment? Was this sample size appropriate for the design of the experiment? What would have happened if the sample size was smaller (for example, sample size = 5)?

1. In the Eckner et al. study, what were controlled variables?

1. In the Eckner et al. study, what were confounding variables?

1. How does the Eckner et al. (2014) article differ from the New York Times article, “A Simple Device to Detect Concussions”.

   1. Which article is easier to read?

1. 1. Which article has more detail regarding the concussion study?

1. 1. Which article is a more reliable source of information? Explain.

1. 1. What is scientific peer-review? Who are the peer reviewers? What are the responsibilities of the peer reviewers?

1. 1. If a Medical Doctor (M.D.) or a Doctor of Dentistry (D.D.S.) discussed the concussion study with a colleague, which publication would she/he likely rely upon? Why?

1. 1. Given that BIOL& 160 students are typically studying to become healthcare professionals who will often be the most direct link between physician and patient, how important is it for BIOL& 160 students to be able to recognize levels of reliability in different forms of scientific communication?