Scientific Design & Method

Ethical Limits

"Do no harm" lab animals sometimes used instead of humans, controversy on testing of animals & humans, before testing on humans & animals studies are done on cell & tissue cultures

Graph-Bar Graph

2 data points=a bar graph

Causation

A cause and effect relationship in which one variable controls the changes in another variable.

Scientific Design: Designing the Experiment

A good design starts with determining variables. An experiment is a procedure used to create a fair test of a hypothesis. A completely fair test is one that shows no bias or favoritism toward any variable, whether controlled or uncontrolled, within the experiment.

Correlation

A measure of the extent to which two factors vary together, and thus of how well either factor predicts the other. Not the cause.

Hypothesis

A proposed, scientifically testable explanation for an observed phenomenon.

Scientific Investigation

A scientific investigation is the way in which scientist study the natural world. First, you ask a question. Then you figure out a way to find the answer.

Scientific Method: Ask a Question Based on Observation Do Background Research Construct a Hypothesis Test Hypothesis with Experiment Analyze Data & Draw a Conclusion Communicate Results (Publish in a Journal)

A way to ask and answer scientific questions by making observations and doing experiments Scientists use the scientific method to search for cause & effect of relationships in nature. They design an experiment so that changes to one item causes something else to vary in a predictable way

Changing Methods

Change containers, work in natural environment

Scientific Design-Why Evaluate

Design of the experiment has everything to do with the conclusions, bad design=invalid conclusions

Avoiding Bias

Experiment not well controlled, other problems not resolved,samples not randomly chosen, control & experimental groups cannot be selective, subjects must be randomly chosen

Replicating

Repeating an experiment to determine whether the findings are reliable, Must be able to be replicated

Statistical inferences

The act or procedure of using statistics from a sample to learn about parameters in a population

Data analysis

The process of compiling, analyzing, and interpreting the results of primary and secondary data results

Spallanzini

proved digestion in the stomach is the result of chemical reactions Responsible for conducting experimenst using flasks of broth - it showed that organisms in the air could cause growth of bacteria

Experimental group

In an experiment, the group that IS exposed to the treatment; contrasts with the control group and serves as a comparison for evaluating the effect of the treatment.

Control group

In an experiment, the group that is not exposed to the treatment; contrasts with the experimental group and serves as a comparison for evaluating the effect of the treatment.

Overcoming Limits

Limit scope of study, do many smaller studies over a longer period, acknowledge the limitations

Scientific model

Makes it easier to understand things that are too difficult to observe directly (too large, too small, dangerous)

Scientific practices & values promote the development of scientific knowledge

New data changes scientific knowledge, change occurs when repetition leads to acceptance, forming & testing hypotheses, evaluating, generating new questions & hypotheses

Graph-Not a usable graph

On a graph 1 data point is not useful

Limits to Scientific Design

Time, money, available equipment, other practical concerns

Emperical evidence

data collected directly by observation or through experimentation

Scientific Knowledge

knowledge obtained through systematic, comprehensive, coherent, clear, and consistent methods.

Natural variables

light, temp, pH, CO2, nutrients

Graph-Line Graph

many data points=line graph, gives validity to data

Changing timing

time measured on a graph can be changed, the longer the time the better the data