Scientific Method is the key to discovery. While not all investigations follow these steps exactly, the steps generally include
- Collecting background information
- Identify the problem (purpose or question)
- Formulate a hypothesis.
- Test the hypothesis.
- Make observations & collect data.
- Draw a conclusion.
Conclusions support or disprove
the hypothesis and are based on the data that has been collected.
Good scientific design can be replicated following the same procedure and yield the same results. RELIABLE data means that the results can be repeated, but VALID data truly answers the question.
In order to insure VALID conclusions, scientists set up CONTROLLED
experiments.
A controlled experiment involves two set-ups:
the EXPERIMENTAL (the one including
the factor which you are testing - also known as the independent variable)
and the CONTROL (the set-up without
the experimental factor).
All the factors other than the one being tested are called the controlled
variables, that is, they are kept constant in both set-ups.
By testing only one variable at a time, the scientistist can tell which factor caused the results.
Scientists identify the dependent variable as the factor that
is being measured, and the independent variable as the WAY in which
the scientist decides to measure (time, distance, presence or absence of
what is being tested).
example: If a scientist is measuring
the effect of adding coffee grinds to the growth of a plant, the dependent
variable is
the growth of
the plant and the independent variable is the presence, absence or concentration
of coffee grinds.
It helps to remember
that the dependent variable is graphed on the Y axis and the independent
variable is graphed
on the X axis.
Think about how you would collect your data and where you would graph it.