170 likes | 293 Views
Scientific Method. Scientific Method. There is no single “scientific method” Most scientific investigations tend to have common stages involved
E N D
Scientific Method • There is no single “scientific method” • Most scientific investigations tend to have common stages involved • These stages include: Making/collecting observations, asking questions, forming hypotheses, testing your hypotheses (experiments), and drawing conclusions
Problems/Observations • Observations are the act of noting or perceiving objects or events using the senses • Every scientific investigation begins with an observation
Questions • Making observations leads to asking questions • Many questions can be answered through observations • In the end, some questions remain unanswered • Evidence is needed to answer these types of questions
Hypothesis • Hypothesis is an explanation that might be true, a statement that can be tested by additional observations or experiments • It is not just a guess, it is an educated guess based on what is already known • A prediction is the expected outcome of a test, assuming the hypothesis is correct
Experiment • An experiment is a planned procedure to test a hypothesis • In a controlled experiment, an experimental group is compared with a control group • A control group is a group in an experiment that receives no experimental treatment • The experimental and control groups are designed to be identical except for one factor, or variable
Experiment • The independent variable in an experiment is the factor/variable that is changed • The dependent variable is the variable that is measured in an experiment Now let’s look at an example..
Experiment • A pharmaceutical company is testing a new drug to improve memory in patients with dementia. They administer this drug to forty patients with dementia and a placebo to forty patients with dementia twice a day for three months. After this time the patients go through a battery of exercises that tests memory. • List the dependent and independent variables and control group:
Types of Experiments/Investigations • Descriptive Investigations are based mainly on observations • Ex. Making models and dissections • Comparative Investigations involve comparing data on different populations or organisms • Ex. Comparing two plants, one with fertilizer and one without • Experimental Investigations are the manipulation of variables (independent and dependent variables with a control)
Conclusions/Inferences • After the data from experiments is collected and analyzed, a conclusion is made as to whether or not the data supports the hypothesis • A hypothesis can be supported or rejected • A hypothesis can be supported but not proven. This is because another experiment with new data and information can alter the conclusion
Conclusions/Inferences • Just because a hypothesis is supported does not mean it is a theory • A theory is a set of related hypothesis that have been tested and confirmed many times by different scientist
Theories VS Laws • In science, for something to be either a theory or law, it has to be tested and agreed upon by many scientists at that time • Scientists typically view theories as: • An explanation for an observation that substantiated by a considerable body of evidence • Explains how nature works • Scientists typically view laws as: • A set of observed regularities expressed in a concise verbal or mathematical statement • Describes what nature does under certain conditions
Theories and Laws Something to keep in mind…. In science, there is no absolute certainty in theories or laws Scientists continually test theories and laws to determine if new data disproves them
Scientific Explanations • At the conclusion of completing the scientific method, a scientific explanation is usually given • This explanation includes: • Claims • Evidence • Reasoning
Claims • Claims are statements that answer your original question • Typically is only one sentence • It must be accurate, specific, and completely answer the question
Evidence • The evidence is all of the scientific data that supports your claim • The evidence can come from a variety of sources • It is important to have numerous pieces of evidence in order to prove your claim
Reasoning • Reasoning is the explanation that connects your claim to the evidence that supports it • It shows why the data you chose counts as evidence • This explanation acts as a conclusion