Transcript Document

A common misperception of science
is that science defines
"truth". Science does not define truth,
but rather it defines a way of
thought. It is a process in which
experiments are used to answer
questions. This process is called the
scientific method and involves several
steps:
Steps of the scientific method:
1. Define the problem - This is usually a question.
Example: "Does acid rain affect the development of
salamanders?"
2. Collect and organize information - Research library
information on:
• Salamanders, acid rain, acids and bases, etc.
• Sources could include: books, journals, internet
articles, etc.
3. Form a Hypothesis (educated guess or tentative
explanation)
The hypothesis is a statement that can be tested.
• Example: "Salamanders that develop under acid
rain conditions show a greater number of
developmental abnormalities than salamanders
that develop in unpolluted waters."
4. Test the hypothesis - EXPERIMENT
Controlled experiment - all the conditions are
alike except the condition being tested.
• VARIABLE - the one condition that is tested
• The EXPERIMENTAL GROUP is exposed to
the variable.
• The CONTROL GROUP is raised under normal
conditions, without the variable.
• Only one variable may be tested at a time.
Variables that depend on each other
(for example- in the case of gases
pressure will depend directly on the
volume of the gas) are called dependent
variables. So if the variable "a" changes
and causes a change in variable "b" then
b is said to be dependent on "a".
Independent variables are those which
do not depend on each other, such as
density and area of a liquid.
5. Observe and record data. Measurements are important.
Always rely on facts not comparisons. The scientist may
use drawings, tables, graphs, diagrams, photographs,
written observations, or sound recordings.
6. Drawing Conclusions
•Conclusions are based on DATA (facts)
•Statistics may be used to evaluate data.
•If a hypothesis is proven to be true over and
over it may be called a law or principle.
•If a hypothesis seems to be true but is unable to
be directly tested, it becomes a theory.
•Theories and laws may have to be replaced as
new evidence becomes available.
A conclusion will often lead to another
question, which will lead
another experiment, which can lead to
another conclusion, and
on and on. Science is like doing a giant
puzzle, with the handicap that you are an
unknown number of pieces. Each new scientific fact is a
Piece of the puzzle. Each new piece can change the appearance
of entire sections of the picture or fit where one did not expect it
to. When scientists have an answer to a question they have
asked, they share their results with other scientists in papers,
magazine articles, lectures, posters or displays at conventions.
This way, new puzzle pieces can be checked out, and the fit
tested. You will present your results at the science fair in the
form of a display.
Test your understanding
Click here:
Practice opportunity.
Test me, I am ready!!!!
Theory vs. Law
A theory or law in the world of science is a
hypothesis, or many hypotheses, which have
undergone rigorous tests and have never been
disproved. There is no set number of tests or a set
length of time in which a hypothesis can become a
theory or a law. A hypothesis becomes a theory or
law when it is the general consensus of the scientific
community that it should be so. Theories and laws
are not as easily discarded as hypotheses.
Science should be fun.. science
should be edible..
Lab Activity:
Purpose: To correctly identify the
independent and dependent
variables.
Title: Fractures in Rollup candy