• What is science?
• Science: an organized way of using
evidence to learn about the natural
• The goal of science is to investigate
and understand the natural world
and to use those explanations to
make useful predictions.
• Thinking like a scientist:
begins with observations which gives data,
qualitative or quantitative (numbers)
• Next, questions are asked and answers are
considered, which leads to forming a
hypothesis: a proposed scientific
explanation for data which can be tested!!!
• Scientists collaborate and share data
and discuss experiments.
–Designing an experiment:
1. Ask a question
2. Form a hypothesis
3. Set up a controlled experiment
4. Record and analyze data
5. Draw a conclusion
6. Repeat the experiment!!!!
• Manipulated variable: the one thing
that changes in an experiment.
(Everything else is the same.)
• Responding variable: the item that
changes as a result of the
• Example: Redi’s experiment
If possible, experiments should have
only one manipulated variable,
everything else should be kept the
same or controlled.
Why are controlled experiments
• If a hypothesis is supported by
repeated experimentation, it may
become a theory.
–A theory is a well-tested explanation
for a broad set of observations.
–A theory may need to be changed at
some point in the future to explain
new observations or experimental
• A scientific law is a concise
statement that summarizes the
results of many observations and
• A scientific law doesn’t try to
explain. That explanation requires a
Hypothesis- an explanation
Experiment- tests hypothesis
Theory- an explanation that has been verified
by so many different experiments that
we agree it is TRUTH.
Scientific Law- states what happens
LAW- Boats disappear on the horizon
Old hypothesis- the world is flat
Current theory- the world is round
Biology: the study of life
• Characteristics of living things:
–Made of cells
– Reproduce (sexual or asexual)
–Universal genetic code (DNA)
– Grow and develop
–Obtain and use material and energy
–Respond to their environment
–Maintain a stable internal environment
–Change over time (evolve)
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