Transcript Nature of Science/Scientific Method Unit 1, Notes

Nature of
Science/Scientific
Method Unit 1, Notes
What Is Science?
The goal of science is to:
– investigate and understand the natural world
– explain events in the natural world
– use those explanations to make useful
predictions
In short, science is an organized way of
using evidence to learn about the natural
world.
Questions to Consider
How can we determine if something is fact or
opinion?
How can we determine an answer to a
problem?
ANSWER…
THE SCIENTIFIC METHOD!
Step 1
Ask a Question
- define the problem
- make sure only one problem is being studied
based on your observation
- observations are made by using your 5
senses
touch
smell
hearing
taste
sight
Step 2
Research the problem
– use all available resources to collect data on
the subject being covered.
– Ex: library, internet, books, magazines,
interviews, etc.
Step 3
Develop a Hypothesis
-- educated guess
– make it a short and definitive statement
– it should be in “If….” “Then….” format
– the “if part” is the hypothesis
– the “then part” is what you think the results
will be at the end of the controlled
experiment.
– a hypothesis can be changed.
Step 4
Develop a Controlled Experiment
– contains only one experimental variable, known as
the manipulated variable. I.E. the thing being tested
– Everything else in the experiment or all other
variables must be the same.
– called constant variables
– keeping these the same allows the
scientists to show that it was the
experimental variable that caused
the results.
Variables in a
Controlled Experiment
Manipulated Variable: the variable you are testing;
also called independent variable
Control Set-Up: what you compare to, no
manipulated variable used
Responding Variable: variable you measure;
changes in response to the manipulated variable
Constant Variables: consistent between all trials
Step 5
Record and analyze the data
– the data may or may not support the
hypothesis.
– if the data proves the hypothesis wrong, change
the hypothesis, not the data.
– if the data supports the hypothesis, additional
experimentation must then take place to build
documentation to support the hypothesis
Types of Data
Quantitative Data
- expressed as numbers
- obtained by counting or measuring
- Ex: 50 ml, 800 km, 45 sec
Qualitative Data
- descriptive
- Ex: clear, spherical, smooth
Step 6
Draw A Conclusion
- use the evidence to support
or refute the hypothesis
- a proven hypothesis must
stand up to additional testing
- other scientists repeat each
others investigations
Step 7: Peer Review
Scientist will share findings and
collaborate with other scientists.
Other scientists MUST be able to replicate
the experiment and get the same results.
Example:
Ask a question, identify problem: Is Raid the
best insecticide on the market?
Research: Look up information on
insecticides , what are the active ingredients,
how many insects will it kill, how much does it
cost, etc..
Hypothesis: Raid is the best insecticide on the
market. It will kill insects 30% faster than
other insecticides.
Experiment:
– Spray 5 plates with equal amounts of 5
different insecticides.
– Cover each one with the same type and size
of glass.
– Add equal numbers of the same species of
insect to each plate. Place the plates side by
side.
– Time the results
– Observe and record the number of
insects that die.
Collect data and analyze: This is done by writing
down the # of insects that died or how fast they
died and then organizing that information into a
graph so you can better see what happened in the
experiment.
Conclusion: This is done after the data from the
experiment has been collected and analyzed. In
this step you will find out if you were correct and
Raid was the best or if your hypothesis was
rejected!
Different Types of
Scientific
Investigations
Descriptive, Comparative and
Experimental Investigations
Comparative Investigations
involve collecting data on different
organisms/objects/ features/events, or collecting
data under different conditions (e.g., time of year,
air temperature, location) to make a comparison.
The hypothesis identifies one independent
(manipulated) variable and one dependent
(responding) variable. A fair test can be designed to
measure variables so that the relationship between
them is determined.
Experimental investigations
involve designing a “fair test” similar to a
comparative investigation, but a control is
identified. The variables are measured in an
effort to gather evidence to support or not
support a causal relationship. This is often called
a controlled experiment.
A fair test is conducted by making sure that only
one factor (variable) is changed at a time, while
keeping all other conditions the same.
Descriptive Investigations
Descriptive investigations involve collecting
qualitative and/or quantitative data to draw
conclusions about a natural or man-made system
(e.g., rock formation, animal behavior, cloud,
bicycle, electrical circuit).
A descriptive investigation includes a question,
but no hypothesis. Observations are recorded,
but no comparisons are made and no variables
are manipulated