Notes

Notes: Nature of Science and Biology

Chapter 1
What is Science?
The root sci- means “to know”. Science is one way of
investigating the world in which we live. The goal of science is to:
• explore and understand the natural world,
• explain events in the natural world, &
• exercise those explanations to make useful predictions.
Science can only concern itself with
testable things andor observable things.

PRACTICE…
Write 2 observations about your classroom
____________________________________________

Write 2 inferences based on what you see around you
____________________________________________

How Scientists Work
Scientific investigations – describe the way scientists gather
information and test ideas about nature. The Scientific Method
describes only one kind of investigation which is called experimental
research. Other investigations can be descriptive in nature, like
describing a newly found species.
Types of Investigations

Descriptive
involves describing and/or quantifying parts of a natural system

Comparative
involves collecting data on different populations/organisms,
or under different conditions (e.g. time of year, locations,
temperature), to make a comparison

Experimental Investigation
involves a process in which a "fair test" is designed in which
variables are manipulated, controlled and measured in an
effort to gather evidence to support/refute a relationship

Quantitative observation
1. Observe – make an observation of
the world around you. There are two
kinds of observations:
• Qualitative observation – descriptive
observation
Ex: The plant is green.

• Quantitative observation – a numerical
observation.
Ex: The flask contains 12.45 ml. There are 4
pennies.

2. Ask a question – based on your observation,
ask a question to investigate.
Ex. Redi asked the question “How do new living
things, or organisms, come into being?”

3. Research - Look in books, journals and the
internet to make additional observations and
research about the questions you made from
your observation.

4. Formulate a hypothesis - Propose
a scientific explanation to the question
being observed and researched. The
(“Which is statement must be testable.
best?” does not lend itself to being
tested). At the end of the investigation,
you will either accept or reject your
hypothesis.
Ex. If meat is left uncovered, then flies will
leave eggs on the meat, creating maggots.

5. Perform a controlled experiment -
Develop and use the experimental design
to test your hypothesis. Whenever
possible, the hypothesis should be tested
by an experiment in which only one
variable is changed at a time. All other
variables should be kept unchanged, or
controlled.

Variables: Factor within the investigation being tested controlled
•controlled - Variables that are kept constant
•independent- Variable being manipulated (in a
graph found on the x-axis or the horizontal axis)
•dependent- Variable that responds (in a graph
found on the y-axis or the vertical axis)
•controlled group - the group where the
independent variable is NOT applied.
Meaning, nothing is changed. Used for
comparison.

Repeat your experiment - The more times you do it, the more
accurate your data and results will be!!
6. Collect data (measurements) and perform
analysis on the data using graphs and charts

7. Draw conclusions - State whether or
not the evidence supports the hypothesis
based on your data and analysis.

•Please notice that we do not prove
hypotheses! Proof exists when the chance
for error is 0. There is always some chance
for error (no matter how small it is) and this
existence of chance error means we cannot
prove anything in true, honest, science.

8. Report back to the community –
Experiments’ results
can be used by other
to help them with their
own experiments.
This is what keeps
science progressing.

What is the difference between a hypothesis, a theory, and a law?
A hypothesis - A hypothesis is a possible explanation for
a set of observations. It has not yet been
thoroughly tested.
A theory - A theory is a well tested explanation that unifies
a broad range of observations.
•It is widely accepted by the scientific community.
•A theory explains observations simply and clearly,
and predictions can be made from them.
A law - A law is a summary of observed natural
events: they are less comprehensive than
theories and normally are associated with a
mathematical expression. It is also widely
accepted by the scientific community.