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# Lab Topic 1 - PowerPoint PPT Presentation

Lab Topic 1. Science: A Way of Gathering Knowledge. The Scientific Method. Scientific Method = Process which outlines a series of steps used to answer questions.

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### Lab Topic 1

Science: A Way of Gathering Knowledge

• Scientific Method = Process which outlines a series of steps used to answer questions.

• The key ingredient of the scientific process is the hypothetico-deductive method, which is an approach to problem-solving that involves:

• 1. asking a question and formulating a tentative answer or hypothesisbyinductive reasoning.

• 2. using deductive reasoningto make predictions from the hypothesis and then testing the validity of those predictions.

• Educated guess proposed as a tentative answer to a specific question or problem

• Less used terms

• Null hypothesis is the hypothesis stated as a negative

• Alternative hypothesis is the hypothesis

• Inductive Reasoning = Making an inference from a set of specific observations to reach a general conclusion.

• Deductive Reasoning = Making an inference from general premises to specific consequences, which logically follow if the premises are true.

• Usually takes the form of If...then logic.

• In science, deductive reasoning usually involves predicting experimental results that are expected if the hypothesis is true.

• Independent variable

• That which will be varied during the experiment.

• This is sometimes the “cause” of something.

• Graph on X axis

• Dependent variable

• Variable that is measured, counted, or observed in response to experimental conditions.

• This sometimes the “effect”.

• Graph on Y axis

• Control variables

• Other variables that could influence the dependent variable, but which are kept constant.

• Level of treatment

• Intensity, frequency, etc., etc.

• Control treatment

• The independent variable is held at an established level or is omitted

Hypothesis: Increased levels of sulfur dioxide adversely effect plant growth

Group A plants placed in filtered air environment (0% sulfur dioxide)

Group B placed in 3% sulfur dioxide atmosphere

Plant height is measured at 2, 4, 6, 8, and 10 weeks of exposure.

What is the dependent variable?

Height

What is the independent variable?

Time

Hypothesis: Increased levels of sulfur dioxide adversely effect plant growth

Group A placed in filtered air environment (0% sulfur dioxide)

Group B placed in 0.1% sulfur dioxide atmosphere

Group C placed in 0.5% sulfur dioxide atmosphere

Group D placed in 1.0% sulfur dioxide atmosphere

Group E placed in 10.0% sulfur dioxide atmosphere

Plant height is measured at 6 weeks of exposure.

What is the dependent variable?

Height

What is the independent variable?

Concentration of Sulfur Dioxide

The Experiment: effect plant growth

• You are to work as a group to conduct an experiment which will assess recovery time after exercise.

• You should, as a group, decide upon a factor which you believe could have an impact on cardiovascular health. That factor could be age, gender, amount of exercise, diet, etc, etc. etc.

• From your group you will select two individuals that vary in regards to this factor (male-female; youngest-oldest, couch potato-world class athlete, etc.). Those two people will then be your source of data during the experiment.

The Experiment effect plant growth

• As an example …I have chosen smoking.

• In my group I may have had a two-pack-a-day person and a never-touched-the-evil-weed person. They will carryout a standardized Step-Test to document their recovery time after exercise.

• Aside…It is normal for pulse and respiratory rate to climb when you engage in a physical activity…that is what is supposed to happen as your body responds to the increased needs for oxygen and circulation that the exercise state demands.

• When you cease exercising the pulse and respiratory rate should rapidly return to normal. If instead, they remain elevated after exercise cessation…that is bad!

Testing recovery time in smokers effect plant growthvs non-smokers.

• Question: Do smokers have poorer cardiovascular fitness than non-smokers?

• Null Hypothesis: Smokers do not have poorer cardiovascular fitness than do non-smokers

• Alternative hypothesis: Smokers do have poorer cardiovascular fitness tan do non-smokers

Experimental Design effect plant growth

• Step for 3 minutes at 30 steps per minute

• Pulse will be measured before procedure and will be measured at 1, 3, 5, 7 and 10 minutes after procedure.

• Respiratory rate will be measured before procedure and will be measured at 1, 3, 5, 7 and 10 minutes after procedure.

What are the….? effect plant growth

• Dependent variable?

• Pulse Rate and/or Respiratory Rate

• Independent variable?

• Time after exercise

• Controlled variables?

• Gender, age, diet, ethnicity, etc. etc. etc.

• Level of Treatment?

• Step Test 3 minutes @ 30steps/minute

• Control?