1 Observation vs. Inference: In an OBSERVATION, you use one or
more of your five senses to know or determine something. In
an INFERENCE, you make an explanation for the observation.
1.1 An example of an OBSERVATION would be that you see steam rising
over a cup of tea. This is an OBSERVATION because you are using your
senses to determine this. An INFERENCE would be saying that the tea
is hot, because you have used your observation to reach a conclusion.
2 There are three types of variables in most science
experiments: the INDEPENDENT, DEPENDENT,
and CONTROL variables
2.1 An INDEPENDENT variable is the variable that is being changed.
It is also known as the test variable. In a valid scientific
experiment, there is only ONE independent variable.
2.2 A CONTROLLED variable is a variable that remains constant and
unchanged. The CONTROL variable can also be compared to determine
how much of an impact that the independent variable had.
2.3 A DEPENDENT variable is the variable being measured. It is
the variable that is being observed when the independent
variable is being changed.
3 THEORY vs. LAW vs.
3.1 A HYPOTHESIS is an educated guess, based on observation. Usually, a
hypothesis can be supported or disproved through
experimentation or more observation. A HYPOTHESIS can be
proved false, but can't be proven true.
3.1.1 Example: If you have two or more brands of laundry detergent and you see no difference
in their cleaning ability, you might hypothesize that the cleaning effectiveness isn't
affected by what detergent you use. This can be proven false (if you notice that one
detergent isn't as effective, for instance), but cannot be proven true, because even if you
test 100 different detergents, there might be one out there that's different.
3.2 A scientific THEORY summarizes a hypothesis or group of hypotheses that have
been supported with repeated testing. Theories explain why an event takes place.
Theories are valid as long as there isn't evidence to prove it false.
3.2.1 Example: Let's use the Big Bang Theory. This theory states that the universe began as a
small point of condensed energy and then rapidly expanded, making a big bang. The reason
why this is considered as a THEORY is because it explains why or how something happened.
For example, this theory explains how the universe expanded.
3.3 A scientific LAW generalizes a group of hypotheses. Scientific laws
explain that something happens, but they don't describe why.
There are no exceptions to a scientific law.
3.3.1 Example: In Newton's First Law of Motion, it states
that objects in motion stay in motion unless another
force stops it. The reason why this is considered as a
LAW and not a theory is because it doesn't describe
why it happens. We know that this will always happen,
so if we find new evidence on why this occurs, the law
will stay true.