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Presentation 1 class notes - PowerPoint PPT Presentation

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Outline Go over the reading: summarize reactions Intro talk: the scientific method Concepts and frameworks we’ll use Examples from a few readings An overview of today’s lab Prep work and logistics for the lab Assignments, schedule changes, etc Science

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Presentation Transcript
Outline l.jpg

  • Go over the reading: summarize reactions

  • Intro talk: the scientific method

    • Concepts and frameworks we’ll use

  • Examples from a few readings

  • An overview of today’s lab

  • Prep work and logistics for the lab

  • Assignments, schedule changes, etc

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A framework for solving problems and making sense of the world around you

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New College

  • Problem-based seminars

  • Science occupies an embattled, problematic place in our world

  • Conflicts and controversy over the politics of science are frequent and require scientific literacy

  • Hands on experience with the scientific method

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Points to take away from the reading in Angier: intro

  • Science: it’s not just for little kids

  • Misunderstood and embattled, but useful

    • No $, no fame, yet the engine of society

  • Thinking scientifically is underrated

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Points to take away from the reading in Angier: Ch2

  • Science: not just a body of facts

  • Universality of the scientific method

  • Scientists believe there is an objective reality that can be unmasked through tools of science

  • Wonder can be cultivated

  • Quantitative thinking can be helpful

  • Facts, not truth, and science is not opinion

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Points to take away from the reading in Angier: Ch2

  • Bias and bad data are our enemy

    • Experimental design and controls

    • Blinding studies

  • Approaching the same problem via multiple routes is often the best way and gives the findings credibility

  • Science is based on defending your data and conclusions in a peer group of others

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Points to take away from the reading in Angier: Ch2

  • Scientists think in grey tones and often arguments are not well translated to the popular media

  • Scientists are fixated on the unknown and debate: they are attacked on these grounds by non-scientists who fail to understand what science is all about

  • We are often superstitious creatures who believe things with no evidence; most scientists yield only to scientific arguments

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What does scientific literacy mean?

  • Being able to sort out what constitutes science and what does not

    • Good science versus pseudoscience or bad science

  • Comfort with common terms and concepts involved in the scientific method

    • Fluency in scientific language (download vocabulary)

  • The ability to explicitly design, conduct, and communicate a science experiment

  • Attaining an understanding and appreciation of uncertainty and conflicting viewpoints

    • Non-dualistic thinking

    • Understanding of science as a process

  • Scientific thinking is applicable to everything

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Science as process

  • The scientific method is a way of approaching the world around us

  • Not mystical or specialist

  • Usually more questions arise than are answered – more hypotheses are generated

  • Inherently iterative

  • You have to expect that you will be proved wrong. We are all blind men describing elephants.

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  • Usually defined as “an educated guess”

    • What is that?

    • A question that arises from observing the world around us

  • Often includes inherent bias

    • Sometimes no one asks the right questions or only asks questions to which they already think they have the answer

  • Can be the product of inductive or deductive reasoning

    • Inductive reasoning is generalizing

    • Deductive reasoning is

  • Must be falsifiable (Karl Popper) and testable

    • Useful in determining what hypotheses are scientific (or are political, pseudoscientific, etc)

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Scientific method

  • Approximately 11 Steps

  • Process is repeated many times

  • Can NEVER prove a hypothesis

    • Can only reject many, leaving one as best supported by the data

    • “Scientific Proof” is a common fallacy

    • Associations don’t prove causation

    • FACTS not TRUTH

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Scientific method - Steps 1-5

  • Observe or suspect pattern

  • Posit significance of observed difference

  • Create question to explain pattern

  • Create testable hypotheses

  • Design experiment

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Scientific method - Steps 6-11

  • Collect data (descriptive stage)

  • Analyze data, primarily using statistics

  • Evaluate hypotheses, accept or reject them

  • Make conclusions based on data

  • Note problems in current work

  • Predict future directions for research

  • The process is the structure for write-ups

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Parts of a scientific report

  • Title

  • [Abstract - an overall summary]

  • Introduction - background, question, Has

  • Methods - what we did

  • Results - what we found, graphs, summarized data

  • Discussion - interpretations, predictions

  • References - who we cited

  • Document on course website!

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Scientific Communication

  • Written report

    • Traditional

  • Oral presentation

    • Commonly used for preliminary presentation of work to get feedback before writing it up

  • Poster

    • Visual summary of work - used at conferences

  • Web page

    • Can use a written report & make it interactive

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  • Independent variable: one thing that changed (measured)

  • Dependent variable: outcome (measured)

    • This language comes from math: y=mx+b

  • Usually experiments must be repeatable

    • Some are not repeatable or even ethically repeatable

  • Always use controls – snake and tadpoles

  • Ethics and experimental design

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Key concept: reasoning

  • Inductive reasoning:

    • Generalizing: This floor is hard, all floors must be hard

  • Deductive reasoning:

    • (Coming to a conclusion based on premises: all birds have feathers, an ostrich is a bird, so all ostriches have feathers)

  • Key in hypothesis generation and in drawing conclusions from work

  • Often extensions are not valid

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Key concept: errors in analysis

  • Type 1 error: "false positive": the error of rejecting a null hypothesis when it is actually true; observing a difference when in truth there is none.

  • Type 2 error: "false negative": the error of accepting a null hypothesis when the alternative hypothesis is the true state of nature. In other words, this is the error of failing to observe a difference when in truth there is one.

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Key concept: Occam’s razor

  • AKA Law of Parsimony

    • The simplest explanation tends to be the best

      • Often also the least entertaining

      • Means that we’re better off not using our imagination too much when trying to explain natural phenomena

  • Simpler theories are often easier to test, so science is biased in favor of them (K.P)

  • Einstein: OR doesn’t mean simplification is best. Things should be made as simple as possible, but no simpler

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  • Key Concept: the precautionary principle

  • The precautionary principle states that when science is extended and there are risks of irreversible risks to human health or the environment, the burden of proof is on the doer.

  • Species extinction, Global warming, GMOs, Public health, Persistent or acute pollution (endocrine disruptors, asbestos), Food safety (CJD), Artificial life, new designer molecules, etc

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Key concept: Non-Western science

  • Sometimes pseudoscience, often not

  • Ethnobotany, ethnopharmacology, ethno-etc.

  • May be linked with superstition or religion

  • Often provides real insight that can be co-opted by university-trained scientists from rich countries

    • Inoculation/vaccination

    • Geography

  • Under the radar

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In-class readings

  • Identify hypotheses, explain experimental methods and analyses, and discuss outcomes

  • Were controls used? How?

  • How are these experiments similar/different?

  • How did this study contribute to the creation of new knowledge?

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Agriculture lab

  • Woman’s oldest science

  • “Trial and error” and logic are always used

    • Observing what works and what doesn’t

    • Often leads to spurious conclusions

      • Like hanging bags of water on the wall

      • Mangoes and sugar

  • We’ll be using our basic knowledge of the scientific method to explore the effect of soil composition on crop development

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  • NPK

  • Various materials add these macro-nutrients

    • We have a few on hand here

    • Blood meal, bone meal, greensand

    • Composted cow doo doo (scientific term)

  • We want to know whether adding these things to the soil will achieve a measurable increase in plant growth

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Experimental design

  • Three plots, all with different soil types

  • Unimproved soil

  • Soil with composted manure

  • Soil with composted manure and NPK additives

  • Outcome of interest: plant development

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  • We want to know____________________

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Materials and methods

  • Tools we need

  • How do we intend to go about answering this question?

    • Data collection plan

    • Data analysis plan

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  • Pooled class data

  • Graphs and tables

  • Simple statistics

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  • Contextualizing results, explaining sources of error, etc

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  • What did we find? Why does it matter?

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  • Need 6 teams of 3 people

  • Each team visits the garden over the next 6 weeks to record data

  • We’ll analyze data all together and each person writes his or her own lab report

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Need volunteers for these times

  • Week 0: today

  • Week 1: Sept 3-9

  • Week 2: Sept 10-16

  • Week 3: Sept 17-23

  • Week 4: Sept 24-30

  • Week 5: Oct 1-7

  • Week 6: Oct 8-14

  • Visit at your own discretion sometime that week