Scientific Method Explained
What is Science?
The
Goal of Science
1) deals only with the natural world
2) to
collect and organize information
3) propose explanations that can be tested
Science – using evidence to learn about the
natural world; a body of knowledge
Science begins with observations –
often taking data on what you see, hear or smell
data – the information gathered from
observations quantitative data = numbers
qualitative data = descriptive
Inference – a logical interpretation based on prior knowledge or experience (Ex.
You see a window broken and a baseball on the floor next to the
shattered glass. You can -infer- that a baseball broke your window)
Hypothesis – a proposed scientific explanation.
This statement is testable and can be confirmed with experimentation or
further observation.
Prediction – An if-then statement that shows what you expect to see as a result of
an experiment or observation (Ex. If fertilizer makes a plant grow
faster, then seedlings planted with fertilizer will be taller than the ones
planted without fertilizer)
Steps
of the Scientific Method
1) Ask
questions, make observations
2) Gather
information
3) Form a
hypothesis
4) Set up
a controlled experiment
Manipulated variable – the variable that is deliberately
changed (independent variable) Responding variable is variable that is
observed ( aka dependent variable)
5) Record
and analyze results
6) Draw a
conclusion
7) Repeat
Suppose you observed that a cricket
outside your window seems to be chirping every night, but some nights it chirps
faster than others. A friend of yours told you once that you can use the sound
of a cricket chirp to tell the temperature. Curious, you decide to design an
experiment. First you must create a hypothesis; here are some examples
of possible hypotheses:
The frequency of cricket chirps will
change as the temperature changes.
As the temperature decreases, a cricket
will chirp fewer times.
Either hypothesis will work, the
important thing is that you can -test- the hypothesis by doing an experiment
which will confirm or deny the statement.
To set up the experiment, you go out to
your yard and capture a few crickets. You bring them inside and place them in a
container. But wait, if you have a bunch of
crickets together, what if they chirp
based on how many crickets there are nearby. The goal in designing an
experiment is to eliminate all the variables except the one you are testing.
This means all your cricket subject must be housed in the same environment
(same lighting, same food, same water..etc). Okay, so you get that set up and
take the temperature of your room. Now you must wait for the crickets to start
chirping. You count how many times the cricket chirps for a 5 minute period.
Now you have to compare that number with
the chirps that occur at different temperatures. You may use a heating pad, or
ice or any other way to lower or raise their temperature. You would then take
data for 5 minutes at the new temperature.
In your experiment, the MANIPULATED VARIABLE is
the thing you changed – the temperature.
The
RESPONDING VARIABLE is what you are measuring that happens as a result
of that change – the number of chirps.
The CONTROL GROUP isn’t obvious
in this case – but you can consider your original (room temperature) data as
your control, and the other temperatures your experimental data.
After you have taken data, you can then
draw a conclusion about whether your hypothesis is accepted (correct) or
denied (incorrect).
No hay comentarios:
Publicar un comentario