Scientific Method Questions of the Day... What is the “Scientific Method”? Why do scientists use this method? Why is this method effective? How can scientists ensure a conclusion is free from bias? Can anyone utilize this method? How? Why?

Scientific Inquiry Objectives & Standards Analyze components of a scientific investigation Determine if data supports or contradicts a hypothesis. Recognize, analyze and evaluate alternative explanations for the same set of observations Evaluate the accuracy and precision of data. Defend a conclusion based on scientific evidence. Determine why a conclusion is free from bias

Scientific Method

Scientific Method Utilizes “If....Then...” Logic – If A happens then B will happen... Hypothesis is a possible answer to a specific question. “Answer on trial” Process of Trial and Error Deductive reasoning – flows from general to specific... A hypothesis gains credibility by surviving attempts to falsify it. Theory – explanation that is broad, generates new hypotheses, and is supported by a LARGE BODY OF EVIDENCE

Scientific Inquiry QUESTION: Do all scientists follow the scientific method exactly in the order listed? Why or why not?

Scientific Inquiry ANSWER: NO! Scientists in the middle of an experiment may decide that additional information is needed in order to revise (change) their experimental methods. And new questions may need answering!

Thought Experiment Observation: A flashlight with batteries in it is not working. Task: Develop a hypothesis and an experiment to test your hypothesis.

Thought Experiment Your experiment may be... Replace batteries with a fresh set to see if it corrects the problem. Change the light bulb to see if it corrects the problem.

Thought Experiment Your data may be... Batteries correct the problem. Light bulb corrects the problem. Both together correct the problem Neither corrects the problem and the cause of the dysfunctional flashlight remains unknown.

Thought Experiment Each experiment in this exercise may have required further questioning as to why the flashlight did not work. In a lab, scientists may revise experiments if new questions arise during the process. If something does not work, try again and revise the possible answer...the hypothesis.

Scientific Method Questions of the Day... What are the steps of “Scientific Method”? What does the word “control” mean to you? What do you think a “controlled experiment” is? What does the word “accurate” mean to you? Why do you think accuracy is important in science?

Controlled Experiment Scientists usually “control” unwanted variables not by eliminating them, but by canceling their effects by using control groups. Experimental Group vs. Control Group

Types of Data Qualitative – Recorded descriptions the solution is green Quantitative – Numerical measurements the solution has 30 mg of chlorophyll

IV vs DV Independent variable Dependent variable The stimulus in an experiment. Dependent variable The measurable response to the stimulus.

Data: Accuracy vs. Precision How close a measurement is to its true value. important because it tests the validity of your lab equipment. Precision How close a group of measurements are to one another. important in order to reproduce the same measurements.

Data: Accuracy vs. Precision

Data: Accuracy vs. Precision Check! A student uses a scale to measure the weight of a bull frog knowing that the frog's actual weight is 0.50 kg. The student gets the same reading of .35 kg after 15 separate measurements using the same scale. Are the measurements precise, accurate, both, or neither? What is a possible issue in this experiment?

Accuracy vs. Precision Month Length 1 3.9 2 3 4.0 4 4.5 5 6 5.0 An average Great White Shark is 4 – 5.2 meters long The data to the left shows the growth of a Great White Shark. Is it accurate? Is it precise? In what portions? Why? What conclusions can be drawn from this data? (Accuracy and precision)

Analyzing Data 2 Students were given 3 different samples of a solution containing NaCl (table salt) with known concentrations (amounts of salt). After boiling the samples, students collected the residue at the bottom of each test tube and weighed the residue to determine the mass (weight) of the sample. Each student charted their results...

Analyzing Data Student 1's results are listed at the top. Sample # Actual Conc. (mg) Exp. Conc. (mg) 1 50.0 48.3 2 45.0 42.2 3 30.0 25.5 Student 1's results are listed at the top. Student 2's results are listed at the bottom. Which student had the greatest accuracy? What could be said of Student 2's results? What are possible explanations for Student 2's results? Sample # Actual Conc. (mg) Exp. Conc. (mg) 1 40.0 22.1 2 25.0 23.9 3 50.0 15.7

Scientific Method Questions of the Day... What do you think bias means? Give an example of bias. How can scientists combat bias? Do we all have bias? Why or why not?

Free From Bias Why does it mean to be biased? How can a conclusion be determined as free from bias? What methods do you think could help a scientist determine that her/his conclusion does not contain a personal opinion?

Free From Bias

Free From Bias Andrew Wakefield – Falsified data linking autism to vaccines in order to make money... http://www.nytimes.com/2011/04/24/magazine/mag-24Autism-t.html?pagewanted=all&_r=0

Free From Bias A few months ago, yet another new study was published showing further evidence using appx. 1.25 million children to definitively show that vaccines do not cause autism. http://nypost.com/2014/05/19/no-links- between-autism-and-vaccinations-study/

Free From Bias Results are reproduce-able by other scientists not affiliated with you or your company. If results are not reproduce-able, the data is considered invalid. Further questions are raised. Investigations into the scientist's integrity as well as possible fraud charges occur. http://jilard.com/scientist-charged-with-hiv- research-fraud/287769/

Conclusion Scientific method is a problem solving process involving “if...then...” logic IV – stimulus DV – the response measured Data can be measurements or descriptions Accuracy vs. Precision Scientists analyze data to determine conclusions Conclusions are free from bias as they are drawn from observations.

Conclusion Reproducibility is important in order for a conclusion to be considered valid If results can not be reproduced, data from an experiment is considered invalid. Scientists can be charged with fraud for falsifying data, therefore reproducibility is essential.

Scientific Inquiry Objectives & Standards Analyze components of a scientific investigation Determine if data supports or contradicts a hypothesis. Recognize, analyze and evaluate alternative explanations for the same set of observations Evaluate the accuracy and precision of data. Defend a conclusion based on scientific evidence. Determine why a conclusion is free from bias.

LAB Tasks List the steps of the scientific method and what happens in each step. Generate a hypothesis to this question... Can someone tell the difference between Hersheyettes and M&M’s? Develop an experiment to test your hypothesis. Designate a “control group”... List the independent variable and the dependent variable. What kind of data will you collect? Quantitative, Qualitative, or both? Perform the experiment. Chart your results. Draw a conclusion. Peer review your conclusion.