Geology Reference
In-Depth Information
I have a hypothesis!
After you have summarized your observations, it's time to propose an educated guess
about the processes behind the patterns you observe. That educated guess is your
hy-
pothesis.
In everyday speech people often say, “I have a theory” when they really mean “I
have a hypothesis.” (I'll get to theories in a few pages.)
A hypothesis is an inference about the patterns you have observed, based on
your observations and any previous knowledge you have about the topic. It's pos-
sible to have many different hypotheses about the observed patterns. How do you
know which one is correct? You test it with an experiment, which I describe next.
Testing your hypothesis: Experiments
Now the real fun begins: experimenting to determine if one of your hypotheses is cor-
rect. Scientists use their hypotheses to develop predictions that can be tested. Based on
the observations about the color of dog fur, a prediction could be this: “I predict that all
dogs have either brown fur or white fur with black spots.” The prediction is a restate-
ment of my hypothesis, based on my observations.
To determine if my prediction is correct I need to collect more information. I will make
new observations, but this time I will manipulate the situation and observe the out-
come. In other words, this time my observations will be the result of an
experiment.
In science, the
experimental design,
or the way you go about collecting the
new information, is very important. An experimental design describes the para-
meters of your experiment: how many samples you will take (how many observa-
tions you will make) and how you will choose those samples. These decisions are
partly determined by the question you are asking and partly determined by the
nature of the observations you are collecting.
In most cases it's impossible to observe every single instance of the physical world that
you are exploring. Therefore, you must take a sample that can represent the rest. For ex-
ample, I can't look at every dog in the world to see what color their fur is, so I may de-
cide that looking at 100 dogs will provide me with enough observations to determine if
my prediction is correct. Those 100 are a sample of the worldwide population of dogs. If
