We live in a society exquisitely dependent on science and technology, in which hardly anyone knows anything about science and technology.

Transcription

1 We live in a society exquisitely dependent on science and technology, in which hardly anyone knows anything about science and technology. Carl Sagan

2 What is Science? Definition of Science What is the goal of science (biology)? How is science distinct from other academic fields? What isn t Science? Pseudoscience Anecdotal evidence Superstitions

3 Why and when do people develop superstitions?

4 How Do We Study the Natural World? Scientific Inquiry The word Science is derived from Latin and means to know Inquiry is the search for information and explanation. Cause-Effect relationships in nature There are two main types of scientific inquiry: Discovery Science/Observational Studies Describes natural structures and processes based on observation and analysis of data Hypothesis-Based Science Methodical exploration (Scientific Method) A tool to gather and make sense of information What makes science unique!

5 A Systematic Approach in Obtaining New Information Really more of a way of thinking than a set procedure! The Scientific Method

6 The Scientific Method

7 What should you do when something you believe in turns out to be wrong? This may be the most important feature of the scientific method: it tells us when we should change our minds.

8 Why Do Giraffes Have Long Necks? The food competition hypothesis argues that long necks evolved because those with long necks can reach food unavailable to other mammals. Prediction: Giraffes feed high in trees.

9 Simmons and Scheepers tested the food competition hypothesis and found that the third prediction does not hold true. Thus, there may be better alternative hypotheses to explain neck length in giraffes.

10 The Sexual Competition Hypothesis An alternative hypothesis is that giraffes evolved long necks because longer-necked males win more fights than shorter-necked giraffes, and can then father more offspring. Data support this hypothesis.

11 The scientific method is a powerful approach to understanding the world. If science proves some belief of Buddhism wrong, then Buddhism will have to change Dalai Lama, 2005 Science is a way of knowing by accumulating data from observations and experiments, seeking relationships of the data with other natural phenomena and excluding supernatural explanations and personal wishes. -- John A. Moore

12 The Scientific Method & Experimental Design Step #1: Make Observations/Ask a Question! Can all questions be answered scientifically? Are serial killers evil by nature? Does taking echinacea reduce the intensity or duration of the common cold? What is the best recipe for chocolate chip cookies? What determines whether a question can be answered scientifically?

13 The Scientific Method & Experimental Design Step #2: Come up with a hypothesis! What makes a hypothesis scientifically useful? Plants are able to absorb water through their leaves and roots. All dogs go to heaven. Echinacea reduces the duration and severity of the symptoms of the common cold.

14 The Scientific Method & Experimental Design Step #3: Design an experiment to test your hypothesis Independent Variable: what the experimenter deliberately changes Dependent Variable: what is measured as a response to the independent variable Constant (controlled) variables: Everything except the independent variable must be standardized. Only the Independent Variable should be changed! Practice: What is the IV/DV & constant variables for the following? The effect of fertilizer on the yield of tomatoes. The amount of color/pigment removed from beets soaked at different temperatures?

15 The Scientific Method & Experimental Design Question: Does taking echinacea reduce the intensity or duration of the common cold? Hypothesis: Echinacea reduces the duration and severity of the symptoms of the common cold because a component in the plant extract boosts the immune system. Controlled experiment? Independent variable? Dependent variable? Constant (controlled) variables?

16 The Scientific Method & Experimental Design Step #4: Now, come up with a prediction! The prediction is a statement of the expected experimental results based on the hypothesis Hypothesis: Echinacea reduces the duration and severity of the symptoms of the common cold because a component in the plant extract boosts the immune system. Prediction: If echinacea reduces the duration and severity of the symptoms of the common cold, then individuals taking echinacea should get sick less frequently than those not taking it, and when individuals taking echinacea do get sick, their illness should not last as long.

17 The Scientific Method & Experimental Design All experiments require at least one control (and often more than one!) in order to eliminate/minimize the effects of variables other than the single independent variable! Negative control: is a treatment (e.g. a placebo) or a lack of a treatment which should result in no effect/change. This is to ensure that any experimental change is due only to the independent variable (treatment) alone

18 The Scientific Method & Experimental Design Application: Independent Variable Results: Independent Variable Dependent Variable

19 The Scientific Method & Experimental Design Negative control: is a treatment (e.g. a placebo) or a lack of a treatment which should result in no effect/change. Positive control: is a treatment that causes a known change/effect. The positive control is used to confirm that the experimental procedure/technique works according to expectations. That is, the positive control should yield expected results. Can every experiment include a positive control?

20 Skepticism: An attitude of doubt or a disposition to incredulity either in general or toward a particular object. (Merriam-Webster s Collegiate Dictionary, 11 th ed.) From the Greek skeptikos, for thoughtful. Latin derivative is scepticus for inquiring, reflective Therefore, skepticism is thoughtful and reflective inquiry. To be skeptical is to aim toward a goal of critical thinking!

21 shermer_on_believing_strange_things.html

22 The Scientific Method & Experimental Design Practice: What would be an appropriate positive & negative control(s) for the following? The effect of a newly formulated fertilizer on the yield of tomatoes. The amount of carbon dioxide (CO 2 ) produced by yeast when incubated with artificial sweeteners. Bottom Line: Negative and Positive controls provide a basis/benchmark for experimental comparison!

23 Are yeast able to metabolize artificial sweeteners? Bottom Line: Negative and Positive controls provide a basis/benchmark for experimental comparison! Rate of CO 2 Production (ml CO 2 /min) Negative Control (H 2 O) Artificial Sweetener #1 Artificial Sweetener #2 Positive Control (sucrose) But what about a negative control? What would make an appropriate negative control? So what about the positive control? What would make an appropriate positive control?

24 Are yeast able to metabolize artificial sweeteners? Rate of CO 2 Production (ml CO 2 /min) Negative Control (H 2 O) Artificial Sweetener #1 Artificial Sweetener #2 Positive Control (sucrose) Oops! What does this tell you??

25 Are yeast able to metabolize artificial sweeteners? Rate of CO 2 Production (ml CO 2 /min) Negative Control (H 2 O) Artificial Sweetener #1 Artificial Sweetener #2 Positive Control (sucrose) Conclusion?

26 The Scientific Method & Experimental Design Using the scenario for your group, formulate a question, hypothesis and design an experiment to test your hypothesis. Your question Your hypothesis. Your experiment: What will be your independent variable(s) What will be your dependent variable(s) What will be your constant variables? What will be your negative control? Can you have a positive control? What is it? Draw/sketch a graph of the data you would expect if your hypothesis is supported. Draw/sketch a graph of the data you would expect if your hypothesis is not supported.