SCIENTIFIC METHOD

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

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