Unit 1: The Scientific Method Chapter 1-1 & 1-2

Standards Investigation & Experimentation 1a) Select and use appropriate tools and technology (such as computer-linked probes, spreadsheets, and graphing calculators) to perform tests, collect data, analyze relationships, and display data. 1b) Identify and communicate sources of unavoidable experimental error. 1c) Identify possible reasons for inconsistent results, such as sources of error or uncontrolled conditions. 1d) Formulate explanations by using logic and evidence. 1f) Distinguish between hypothesis and theory as scientific terms. 1k) Recognize the cumulative nature of scientific evidence

What is Science? Science is method of thinking about the natural world. Biology is the scientific study of life.

Scientific Method The scientific method is a problem-solving procedure scientists use to seek answers to questions.

THE SCIENTIFIC METHOD PROBLEM HYPOTHESIS EXPERIMENT FORM A NEW HYPOTHESIS REPEAT THE WORK RECORD DATA & ANALYZE RESULTS CONCLUSION ACCEPT HYPOTHESIS REJECT HYPOTHESIS

Scientific Method 1. Identify a Problem 2. Create a Hypothesis 3. Design and perform an experiment. 4. Record Data and Analyze 5. State a Conclusion 6. Repeat the Work

1. Identify a Problem Observations are descriptions about the way something is or the way things happen From these observations, a question is formed about why or how

Example: Identify a problem Barney observes: When I drink Coke, I burp a lot. He asks Professor Frink: Why does Coke cause burping?

Example: Identify a problem Professor Frink explains: You can do background research to help you know more Look online about the physiology of burping

Wikipedia - not always 100% accurate, but a good start for background information carbon dioxide in drinks causes gas pressure to build in the stomach

2. Create a Hypothesis A Hypothesis is a prediction that may provide an answer to the question Must be testable Should be written in the form of an “If…, then…” statement

Example: Create a Hypothesis If people drink Coke, then they will burp more.

3. Controlled Experiment Test the hypothesis Procedure—the steps followed during an experiment Well designed experiments have experimental group(s) & a control group

Example: Experiment Professor Frink wants to determine if Coke will increase the frequency of burping. He gives 10 volunteers (subjects) from Springfield Coke and another 10 subjects water. All other conditions are kept the same. All people are 20-30 years old All people are healthy. All people have to not eat or drink for 3 hours before the experiment.

Subject

Control Group: all variables are kept the same (constant) Used as “normal” for comparison Experimental Group: all the same variables except the one thing you are testing Variables: anything that can influence the outcome of the experiment

Example: Experiment Control Group: people who drink water only Experimental Group: people who drink Coke Variables: age of subjects, health of subjects, having food or drinks before the experiment

Independent Variable: What you are testing The variable that is changed Dependent Variable: what is measured or observed The variable that changes because of the independent variable

Independent Variable: type of beverage Dependent Variable average number of burps Independent Variable Control

The experimental group gets the independent variable-Coke. The control group gets the control-water. Independent Variable Control

4. Record Data & Analyze Collect & record Data (information) Qualitative data: descriptions Quantitative data: numbers Data can be recorded in a table Analyze the data by graphing it Bar graphs: show comparisons Line graphs: show changes over time

Example: Recording Data Average # of Burps Control Group: Water 2 Experimental Group: Coke 6 Dependent Variable: what you measure Independent Variable Control

Analyze the Results: Bar Graph Proper units Title Average Number of Burps for Water vs. Coke Y-axis = Dependent Variable Type of Beverage X-axis = Independent Variable Label

5. Conclusions The results tell whether the hypothesis was “accepted or rejected”

Example: Conclusion Accept or reject the hypothesis? Why? ACCEPT! There were more burps with Coke than with water based on the data and the results of the graph.

6. Repeat the Work When a hypothesis is supported by data from additional investigations, it is considered valid. When a hypothesis is not supported, it means that we need to go back and ask new questions or identify sources of error in the experiment.

Sources of error: things that may effect the results of the experiment Sample Size: more subjects means more accurate results Control all other variables but the one you are testing Length of experiment (hour vs. a day?) Amount of variable (2 cokes vs. 1?) Type of material (coke vs. pepsi?) Other: light, temperature, age, health, male vs. female, etc.

Hypothesis vs. Theory Hypothesis: an educated guess that may or may not be true Theory: a well-tested explanation that unifies a broad range of observations In science, theories are nearly facts Ex. Theory of Evolution, Theory of Relativity, Cell Theory

THE SCIENTIFIC METHOD FORM A NEW HYPOTHESIS REPEAT THE WORK ACCEPT HYPOTHESIS REJECT HYPOTHESIS

THE SCIENTIFIC METHOD PROBLEM HYPOTHESIS EXPERIMENT FORM A NEW HYPOTHESIS REPEAT THE WORK RECORD DATA & ANALYZE RESULTS CONCLUSION ACCEPT HYPOTHESIS REJECT HYPOTHESIS