What’s in the news right now related to science????

• http://www.sciencedaily.com/ • http://www.scientificamerican.com/• Flesh eating bacteria

Chapter 1Java Report

Downloads

• Learning Objectives• Class Discussion and Case study #1 – due

5/23/2012

Coffee Case Study

• Study linked coffee to pancreatic cancer. Second study said NO

• Some say prevent diseases like Parkinson and diabetes

• Concerns about “caffeine overdosing”• Are warning labels needed on certain drinks– Are researchers and journalists making a lot of

mistakes? Is there confusion over the nature of science?

What is science?

• Science is the process of using observations and experiments to draw evidence-based conclusions.– Science is not just a body of established facts; it’s

a way of knowing.– The process is not always easy and

straightforward

How do scientists draw conclusions?• Scientists draw conclusions from the best evidence they

have at any one time.– Conclusions may be modified in the future as other

scientists ask different questions or use improved technology to uncover better data.

How do scientists draw conclusions?

• To properly evaluate a scientific claim, we need to look closely at how the science was done.

Look at Infographic 1.1

Steps of Scientific Method

• Scientists use the steps of scientific method to perform experiments– Observation– Question – Hypothesis

• Prediction

– Experiment– Conclusions– http://www.youtube.com/watch?v=j7YHHPLcHsQ&feature=related – http://www.youtube.com/watch?v=RmawlZCEegg&feature=related

Science is a process: Asking questions

• Anecdotal evidence is an informal observation that has not been systematically tested.– Anecdotal evidence can lead

to the formulation of questions.

– Read information in journals– Often unreliable

Science is a process: Studying previous research

• Peer review is a process in which independent scientific experts read scientific studies before their publication to ensure that the authors have appropriately designed and interpreted their study.

• Weed out sloppy research

Science is a process: Studying previous research

• Reading relevant peer-reviewed literature helps to give a sense of what information currently exists on the subject of interest.

Science is a process: Forming scientific hypotheses

• The information in peer-reviewed literature can be used to formulate a scientific hypothesis – a testable and falsifiable explanation for a scientific observation or question.

• Tentative answer to the question• Example:

– Drinking coffee improve memory

Science is a process: Forming scientific hypotheses

• Scientific hypotheses must be testable and falsifiable.– A hypothesis is testable if it can be supported or

rejected by carefully designed experiments or nonexperimental studies.

– A hypothesis is falsifiable if it can be ruled out by data to show that the hypothesis does not explain the observation.

Science is a process: Forming scientific hypotheses

• Not all explanations are scientific hypotheses.– Statements of opinion, and hypotheses that use

supernatural or mystical explanations that cannot be tested or refuted, fall outside the realm of scientific explanation.

Science is a process: Forming scientific hypotheses

• Hypotheses can never be proved true once and for all!!!!

– If a hypothesis is shown to be false, it can be rejected and removed from the list of possible answers to the original question. Data does not support the hypothesis

– If the data support the hypothesis, it will be accepted until further testing and data show otherwise. It is impossible to test whether a hypothesis is true in every possible situation. Data does support the hypothesis.

Science is a process: Experimentation• Scientific hypotheses can be tested using experimentation.

An experiment is a carefully designed test, the results of which will either support or rule out a hypothesis.

Science is a process: Experimentation• Controlled experiments use experimental

groups and control groups to test a hypothesis.

Science is a process: Experimentation

• The experimental group is the group in an experiment that experiences the experimental intervention or manipulation.

• The control group is the group in an experiment that experiences no experimental intervention or manipulation.

Science is a process: Experimentation• The independent variable is the variable, or factor,

being deliberately changed in the experimental group. Treatment or condition under study. “Cause”

Science is a process: Experimentation

• The control group receives a placebo – a fake treatment given to control groups to mimic the experience of the experimental groups.

– The placebo effect is the effect observed when members of a control group display a measurable response to a placebo because they think they are receiving a “real” treatment. In order to rule this out, the participants in the experiment do not know whether they are receiving a placebo or the experimental treatment.

Science is a process: Experimentation• The dependent variable is the measured result of an

experiment. It is analyzed in both the experimental and control groups. Measured or observed in exp.

Science is a process: Experimentation• In a controlled experiment, the control group and

experimental group differ only in the independent variable, so the results of the experiment provide evidence-based conclusions.

Science is a process: Drawing conclusions

• Confidence in scientific findings is increased by repetition of an experiment by other scientists.

Science is a process: Drawing conclusions

• The sample size of the experiment can strengthen our confidence in the results of the study. The sample size is the number of experimental subjects or the number of times an experiment is repeated.– In human studies, the sample size is the number

of subjects.

Science is a process: Drawing conclusions

• The larger the sample size, the more likely the results will have statistical significance. Statistical significance is a measure of confidence that the results obtained are “real,” rather than due to random chance.

• New reports love statistics.• Always note the sample size in their statements

Science is a process: Drawing conclusions

• The more experiments that support a hypothesis,

• A hypothesis that continues to hold up after many years of rigorous testing may eventually be considered a scientific theory.

Science is a process: Drawing conclusions

• Scientific theories are different than everyday theories. In science, a theory is a hypothesis that has never been disproved, even after many years of rigorous testing.

Look at Inforgraph 1.5

Science is a process: Publication• Results of an experiment are published in

peer-reviewed journals. The studies in these scientific journals are reviewed by experts before publication to ensure accuracy.

Finding patterns

• Scientists can make careful observations or comparisons of phenomena in nature to answer questions that could not be tested through controlled laboratory experiments for ethical or practical reasons.

• Epidemiology is the study of patterns of disease in populations, including risk factors.

Finding patterns• Correlation is a

consistent relationship between variables. Data may show correlation between two variables, but it does not prove that one variable causes the other.

Finding patterns

• Randomized clinical trials, or controlled medical experiments in which subjects are randomly chosen to receive either an investigational treatment or a placebo, are used to measure the effects of a variable under controlled conditions.

Finding patterns

• Scientific studies of drugs can be complicated due to side-effects.

• Max dose 300 mg/day

• Some consume up to 1,400 mg/day

Evaluating scientific information

• It is important to be cautious when making decisions based on a single epidemiological study.– Complexity of a disease makes it unlikely that

every variable can be controlled for.– Small sample sizes can influence accuracy of

results.– The specific population of the study may not be

representative of the general population.

Evaluating scientific information• Scientists rely on peer-reviewed scientific reports to learn about new

advances, but the public often relies on brief media reports that are not always completely accurate in their portrayal of the conclusions of scientific studies.

Ryan’s study

• Observation– Memory is often optimal early in the morning for

adults over 65 and declines as the day goes on.– Adults more alert after drinking caffeinated coffee

• Question– How does coffee affect memory?

• Hypothesis– Drinking coffee might prevent this decline in

memory

• Experiment– 40 men and women over the age of 65 healthy– One group received caffeinated (experimental) one decaf

(control)– Memory test (8am) and test (4pm)– Independent variable (effects of caffeine)– Dependent variable (memory)

• Results– Decaf drinking did poorly on afternoon test. Caf did better on

both test• Conclusion

– Support the hypothesis that caffeine improve memory