Transcript What is Science?

WARM-UP:
On page 4 of your notebook,
write:
What is Science?
How does science
work? What is the
purpose of science?
Set up Notebook
How to Take Notes in Biology
Class

Paste to page 1 of notebook (first page after Table of Contents)
What is science?
How does science work?
What is the purpose of
science?
Scientific Method
Notes
(page 2)
Science is a
process by
which we try
to understand
how the
natural world
works.
It extends the
curiosity with
which we are
born.
Science is…
 A search for understanding
 Limited to the natural world
 Observable
 Testable, Measurable, Repeatable
 Modifiable (open to change)
 Disprovable
 Biased
 Based on experimentation
 Made stronger by different lines of
evidence
Science is NOT….
 Based on belief or
faith
 Based on authority
 Decided by debate
or law
 Rigid
 Able to solve all problems
 A collection of facts
Science asks questions:
What’s there?
How does it work?
How did it come to be this way?
The purpose of science is to
learn about the universe.
Science is based on
the idea that our
senses, and
extensions of those
senses through the
use of instruments,
can give us accurate
information about
the Universe.
How science works…
Science relies on observable
evidence from the natural world.
This includes evidence of past events
(geology, evolution, fossils) and those
that are difficult to see (atoms,
molecules).
How science works…
The Scientific Method
Making Observations
Formulating Questions
Collecting Background Info
Forming a Hypothesis
Testing the hypothesis through
observational studies or
experiments (Procedure)
Examining Results of test
Drawing Conclusions
Forming a new modified
hypothesis
Re-testing the new hypothesis
Two Types of Observations
Qualitative
A description
using adjectives.
Example: The
rock has black
ridges along the
edge and a white
spot in the middle.
Quantitative
A description
using numbers
to quantify.
Example: The
bean plant is 12.5
centimeters tall
and it has 3 new
leaves.
In science, Questions are always asked!
 Why did this plant grow taller than
that one?
 How do gorillas communicate with
their young?
 How do cells obtain energy?
 How can birds fly?
 Why do cakes rise in the oven?
 Why do apples turn brown once
they're cut?
 How does the brain store memory?
Because people have studied the natural world
for such a long time, there is a lot of scientific
knowledge already.
So, one step in the scientific process is to
gather background information- read
books, take classes to learn about the
subject, ask experts.
Observations and Background Info help us
make inferences.
Inference- logical
explanation based on
observable facts.
 For example, you see a plant
wilting on a hot day. What do
you infer?
 Inferences help us design
thoughtful experiments.
 Knowing the difference
between an observation and
an inferences is important in
an experiment.
Identifying Variables in an Experiment
 The independent variable is what the
experimenter changes during the experiment.
 The dependent variable is what the
experimenter measures.
 The standardizing variables are things that are
kept equal so that any changes in the
dependent variable can be attributed to the
changes in the independent variable.
 The control group is when the independent
variable is eliminated or set at a standard value.
Identifying Variables
 Complete the worksheet.
(10 pts)
Next, develop a hypothesis!
A hypothesis is an explanation to a
question that is testable. It predicts
how one variable will affect another.
A hypothesis is formatted like this:
“If… then…”
Example: If one plant is grown in the
light and another plant is grown in the
dark, then the one grown in the light
will survive while the one grown in the
dark will not survive.
Writing Hypotheses
Write Hypotheses on the handout.
10 points
How science works…
Scientific explanations are
tested through
observational studies or
experiments. If the
hypothesis doesn’t work, it
is rejected and revised.
Drawing Conclusions
Hypotheses can be
supported or rejected, but
never proven.
How science works…
Scientific claims are
subject to peer
review and
replication.
 If it can’t be replicated,
it isn’t accepted.
 This is why a wellwritten procedure is so
important!
Science is done collaboratively.
Disagreement is the fuel
between scientists. It helps
them develop better ideas and
come to more accurate
conclusions.
Good science requires
constant questioning.
So… always ask questions!
Constructing a Theory
A collection of hypotheses that have been
repeatedly tested and are supported by a
great deal of evidence forms a theory.
Theories are based on evidence, allow
scientists to make valid predictions, and
have been tested in many ways.
Examples:
 Theory of gravity
 Cell theory
 Evolutionary theory
Theories and “Truth”
 No theory is ever accepted as
absolute “truth” in science.
 All theories are expected to be
further tested no matter how many
previous tests have been done.
 Models and theories, not truth, is
what science produces.
Science exists in a cultural context.
Scientists are influenced by
the culture and time period in
which they live. This
influences what and how they
study.
Example:
 Before Galileo, geocentrism was
the rule. The geocentric model of
the Universe persisted for
centuries. Eventually, people
came to accept that the Earth is
not the center of the Universe.
Science changes.
Science is always a work in
progress, and its conclusions are
tentative.
All ideas are open to scrutiny.
Practice: You conduct an experiment with three mice.
You want to know what type of food they prefer. One
mouse gets cheese, one gets carrots and the other
one gets regular mouse food. You give them each 10
grams of food every day and you measure how much
is left after they are done eating.
 What is your independent variable?
 Dependent variable?
 Control group?
The Scientific Method
Isopod Lab!
Scientific Method:
Senses Lab
 Imagine you want to know which sense is
fastest- sight, touch, or hearing.
 You have decided to design an experiment
to test this question.
 You have a ruler and a lab partner. You will
drop the ruler and your lab partner will catch
it. You will do it with each of the following
senses: sight (they watch you drop it), sound
(you tell them, “NOW”) and touch (tap their
shoulder).
 What is your Hypothesis?
Experimental Error
An error during an
experiment in detection
or measurement due to
inadequate technique or
the uneven application of
measuring techniques.
Accuracy vs. Precision
The accuracy of a measurement
system is the degree of closeness
of measurements to the actual
(true) value.
The precision of a measurement
system, also called reproducibility or
repeatability, is the degree to which
repeated measurements under
unchanged conditions show the
same results.