Physical Science
Chapter 3 Section 1
Inquiry and the Scientific Method
Learning Goals
* Apply deductive reasoning skills to solve problems. *Contrast hypotheses, theories, and laws.
*Explore the scientific process and apply steps of the scientific method.
Inquiry and the Scientific Method
*Scientists believe the universe follows a set of rules called natural laws.
*A natural law is a theory that has been tested many times without any contradictions.
*The primary goal of science is to discover these natural laws and what they mean.
* Learning about science by asking questions is called inquiry .
*An inquiry is like a crime investigation with a mystery to solve.
Inquiry and the Scientific Method
*Solving the mystery means accurately describing who did what, when they did it, and how.
*The problem is that the detective never actually saw
what happened.
*The detective must deducewhat happened in the past from information collected in the present.
Inquiry and the Scientific Method
Demo!!!
*Scientific evidence must be objective. *“Objective” means the evidence should describe only what actually happened as exactly as possible. *It is reported without bias or opinion.
*Scientific evidence must be repeatable.
*“Repeatable” means that others who look the same way at the same thing will observe the same results.
Galileo’s drawings of the moon
More evidence of lunar cycles.
Scientific Evidence
Inquiry and the Scientific Method
Scientific evidence may include numbers, tables, graphs, words, pictures, sound recordings, or other information.
It is important that scientific evidence be communicated clearly, with no room for misunderstanding.
*A
theory
is a scientific explanation
supported by a lot of evidence
collected over a long period of
time.
*For example, understanding heat
puzzled people for a long time.
Inquiry and the Scientific Method
*Because
evidence
is so important in
science, there are careful rules defining
what counts as scientific evidence.
*The evidence must accurately describe
what happens in the real world.
Inquiry and the Scientific Method
Scientific theories
Before 1843, scientists believed (a theory) that heat was a kind of fluid (like water) that flowed from hotter objects to colder objects.
*They called this fluid
caloric.
*The caloric theory explained what people knew at the time.
*However, a big problem came up when people learned to measure weight accurately.
*The caloric theory was soon given up because it could not explain this new evidence.
*One of two things can happen when new evidence is found:
1. The current theory correctly explains the new evidence.
Or,
2. The current theory does not explain the new evidence so a new (or improved) theory is waiting to be discovered.
Scientific theories
*The word theory in science means a single explanation is supported by lots of evidence collected over a long period of time.
*Theories in science start out as hypotheses.
Scientific theories
*A scientific hypothesis must be testable. *We collect evidence that supports or refutes the hypothesis.
Scientific hypotheses
Hypothesis = A testable explanation for a problem.
Scientific experiments
* Experiments done by James Joule in 1843 were confirmed over many years and became the theory of heat we accept today.
*A hot cup of coffee has more heat energy than a cold cup of coffee.
*As coffee cools, it’s heat energy is transferred to the room.
*As a result, air in the room is warmed, but no change in weight or mass can be detected in the two cups.
Scientific theories
The Scientific Method
1. Scientists observe nature, then develop or revise hypotheses about how things work.
2. The hypotheses are tested against evidence collected from observations and experiments.
3. Any hypothesis that correctly accounts for all of the evidence from the observations and experiments is a potentially correct theory.
*The scientific method is the underlying
logic of science.
*It is a careful and cautious way to build
an evidence-based understanding of our
natural world.
*Each theory is continually tested against
the results of observations and
experiments.
*Such testing leads to continued
development and refinement of theories
to explain more and more different things.
The Scientific Method
Classwork 3.1 Section Review
Homework Read 3.2
Physical Science
Chapter 3
Section 2 Experiments and Variables
Learning Goals
* Define experiment.
* Contrast experimental and control
variables.
* Discuss how experiments are carried out
and the importance of communicating
results.
*An
experiment
is a situation
specifically set up to investigate
something.
*The goal of any experiment is to
understand the relationship between
variables.
*A
variable
is a factor that affects how
an experiment works.
* The variable you change in an
experiment is called the
experimental
variable or the independent variable
.
*The variable that changes because you
change the independent variable is
called the
dependent variable
.
*The variables you keep the same are
called
control variables
.
*Each time you run the experiment is
called a
trial
.
See if you can identify each component
in this experiment…
Experimental (Independent) Variable Dependent Variable Trials Control Variable Control Variable Control (Location of gate)
3.2 Experimental techniques
* Your
experimental
technique
is how you
actually do the
experiment.
* The
procedure
is a
collection of all the
techniques you use to
do an experiment.
3.2 Experiments then and now
Electric current is created when a coil rotates in a magnetic field.
*Michael Faraday, a British scientist, made some important discoveries while experimenting with electricity and magnets. *Faraday’s original question was “How are electricity and
magnetism related?”
3.2 Experiments then and now
*Earth is like a giant
magnet.
In 1996, NASA
conducted a modern
version of *Faraday’s
electromagnetism
experiments using a
tethered satellite.
Classwork
*Page 67 #1-3, 5a-e
*Read 3.3
Homework
Physical Science
Chapter 3
Section 3
The Nature of Science and Technology
Learning Goals
*Examine the importance of ethics in
scientific research and reporting.
*Discuss examples of how science helps
to solve problems.
*Consider the role of engineering in
scientific and technological
advancements.
*Truthful reporting is the most
important tradition of science.
*Scientists often write a report of their
experiments and submit it to a
scientific
journal
.
*
Technology
is the
application of
science to meet
human needs and
solve problems.
*Technology arises
from a need for
things to be done
better.
People who design technology to solve
problems are called
engineers
.
Classwork
*3.3 Section Review
*Page 71 # 1, 3, & 4
