Bio 2 – 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. Analyze experimental results and identify possible sources of experimental error.

Bio 2 – Scientific Method Answer the Questions Below... 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 Method

Scientific Method Utilizes “If....Then...” Logic Hypothesis is a tentative answer to a well framed question. “Answer on trial” 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 in textbooks? Why or why not?

Scientific Inquiry ANSWER: NO! Scientists in the throws of an experiment may decide that additional information is needed in order to revise 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.

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 Quantitative – Numerical measurements Qualitative – the solution is green. Quantitative – the solution has 30 ug of chlorophyll.

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

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

Data: Accuracy vs. Precision

Data: Accuracy vs. Precision What kind of information can a scientist learn if data shows that a measurement is not accurate but precise? What would be a solution to this problem?

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?

Analyzing Data 2 Students were given 3 different samples of solution containing NaCl with known concentrations. After boiling the samples, students collected the residue at the bottom of each test tube and weighed the residue to determine the mass 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

Free From Bias

Free From Bias Why is a conclusion free from bias? How can a conclusion be determined as free from bias? What methods do scientists put into place to ensure that the conclusion they have is free from a personal opinion?

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 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.

Bio 2 – 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. Analyze experimental results and identify possible sources of experimental error.

Task Scientific Paper on Microrobots for Ocular Surgery (Eye surgery) http://www.iovs.org/content/54/4/2853.long Identify the portions of the paper that relate to the scientific method. Briefly discuss what the question (purpose) is, the experiment, what the data is, and the conclusion. What tools and lab equipment did they use in the experiment? What were the function of these tools? What type of data did they collect? What was the IV and DV? How could these scientists reinforce their conclusion and give it validity? How is the data presented to show the accuracy and precision?