1.3: Scientific Thinking & Processes

1.3: Scientific
Thinking &
Key concept: Science is a way of thinking, questioning, and
gathering evidence.
• Science is a process of trying to understand the world around
us using critical and logical thinking to evaluate results and
• Scientists gather evidence and share their findings with one
• Observation: the use of our senses, computers, and other
tools to gather information about the world.
• Ex.: Studying the interactions between gorillas by observing their
Observations can be recorded
as data to be analyzed
• Qualitative data: Descriptions of phenomena that can include
sights, sounds, and smells.
• Quantitative data: Characteristics that can be measured or
counted such as mass, volume, and temperature; Numbers
Scientists use observations and
data to form hypotheses
• Hypothesis: A proposed, testable answer to a scientific
• Formal hypotheses are usually written in an “if, then, because”
• If (change of IV) then (change of DV) because (why you think this
will happen).
• If I change the light bulb then my light will work because the bulb
was bad and I replaced it.
• If I increase my blood pressure medicine then my blood pressure
should come down because I still suffered from high blood
How do scientists test
• The scientific method
• A) Observe and ask questions that lead to a problem
• B) Form a hypothesis
• C) Test the hypothesis with a controlled experiment by making
observations and gathering data.
• D) Analyze gathered data
• E) Reject (start over at step B) or Accept your hypothesis.
• F) Form a conclusion
• This is what you will do every time you
conduct a lab in this class!!!!!
How do scientists test
• Controlled experiments study the effect of independent
variables on dependent variables.
• Independent variable: A condition that is manipulated, or
changed, by a scientist. Effects are measured by changes in
dependent variables.
• Dependent variable: observed and measured during an
• Example: Testing medication to treat blood pressure. IV:
medication dose, DV: blood pressure.
Controlled experiments
• Only one independent variable should be changed in an
• Other conditions must stay the same and are called constants.
• Controlled experiments must have a control group –
everything is the same as the experimental groups but the
independent variable is not manipulated.
• Example: When testing blood pressure medication, control group
receives none of the active ingredient.
• A large number of test subjects or trials is ideal.
Other important science terms
• Inference: A conclusion reached on the basis of evidence and
reasoning. (Ex: you make an inference when you use clues to figure
something out). Ex: Murder mystery book
• Law: A law that generalizes a body of observations. At the time it is
made, no exceptions have been found to a law. It explains things but
does not describe them; serves as the basis of scientific principles.
(Ex: Law of Gravity, Newton’s Laws of motion).
• Theory: A proposed explanation for observations and experimental
results that is supported by a wide range of evidence – may
eventually be accepted by the scientific community. (Ex: Big Bang
Theory, Evolution & Natural Selection)
• Principle: A concept based on scientific laws and axioms (rules
assumed to be present, true, and valid) where general agreement is
present. (Ex: Buoyancy Principle)
• Fact: An observation that has been repeatedly confirmed.