Welcome, fellow scientists! Bea here. Since, like, fooorever, scientists have tried to explain
why events in the natural world happen. But with only primitive technology,
like the wheel, available for use, how did scientists explain scientific phenomena
thousands of years ago? Certainly, they must have guessed, right? Hmm... Oh, I know. Do you
think they could have based their explanations on opinion and not science? Nope! Throughout time,
scientists have explained events in the natural world the same way they do today: by carefully
observing the world and designing tests to determine whether or not their theories are valid.
Today, we call this process of scientific inquiry the scientific method. Although the exact methods
used in the different sciences vary – for example, meteorologists and paleontologists work in
very different ways – they still share the core principles of this scientific method. As you'll
find out in your post-lesson resources, the development of the scientific method was not
a linear process; instead, it was a fascinating and long one, spanning thousands of years and
involving many different cultures, as well as some of the greatest minds in science, philosophy,
and theology. So grab a snack and come right back, because in today's lesson, we'll identify
the steps of the scientific method and explore the scientific process through the scientific method.
Welcome back! Typically, the scientific method is taught as a simple six-step method for
performing scientific investigations. Though the six steps include many valuable elements,
they are often misinterpreted and seen as a quick and easy recipe for scientific inquiry.
Would you like to make the perfect scientific conclusion? No problem!
Simply pull a question from the cupboard, throw in a dash of observation, mix in a hypothesis,
sprinkle on some data, put the whole experiment in the oven at 375 degrees, and voila!
30 minutes later, you'll have a perfectly prepared conclusion, fresh from the oven.
Maybe that might work if science was like baking a cake, but science is complex,
and scientists can't explain it with a one-size-fits-all
recipe. Even though the steps of the scientific method are simplified,
collectively, they give scientists a model to work through when trying to understand the world.
Though different fields may have variations on the model, the basic scientific method
begins with making observations with our five senses: sight, sound, smell, taste, and touch.
In other words, you notice something such as the air temperature during the winter.
What happens when ice cream melts or how your plants behave when you forget to water them? These
observations then generally lead to questions. For example, after devouring a delicious dinner,
you and the fam set out to your local ice cream shop to indulge in a post-dinner dip. You place
your order, and the attendant hands you a waffle cone full of ooey gooey dark chocolate ice cream.
You grab it and swiftly set about chowing down on your frosty treat. Your parents pay the bill –
thanks, mom and dad – and you begin your savory stroll back to the car, when suddenly you see
and feel a river of dark chocolate ice cream streaming down your hand and making a sticky mess.
Without even knowing it, you've just completed the first step in the scientific
method – making an observation. You ask yourself frantically, "How did this happen so fast?!"
And although that's a question, it's not a scientific question.
Scientific questions must be testable and answerable. So instead of asking yourself,
"How did this happen so fast?" a good scientific question would be "Does the color of ice cream
affect the time it takes to melt?" or "Does the type of container affect the melting rate of ice
cream?" Because we can test and answer both of these questions, they are considered scientific.
Asking a scientific question is the second step of the scientific method, but we're not done
just yet. There are a couple of other guidelines we must remember when asking
scientific questions: We can't ask questions that are too open-ended or based on opinion, such as
"Does dark chocolate flavoring make ice cream taste better?"
or "Why is dark chocolate ice cream the best flavor in the world?" These types of
questions don't make good science because they're answered with our opinions, not observations.
Regardless of what you might have observed as the river of melted ice cream streamed down your arm,
it's best practice to review existing research on your topic. For example,
is anyone else researching the melting rate of ice cream? If yes, what did they find out? Do you
think you should repeat their research to see if you can duplicate it? During this process, you may
learn new information that allows you to change or refine your question during your research.
From here, you're ready for step three of the scientific method – form a testable
hypothesis. A hypothesis is the cornerstone of the scientific method. It's an educated guess
that integrates knowledge with observation. A hypothesis must be testable, but there is a much
stronger requirement that a hypothesis must meet. A hypothesis is considered scientific only if
there is the possibility to disprove it by direct experiment. Quite often, hypotheses are written
as if-then statements. For example, I might hypothesize, "If ice cream is dark in color,
then it will melt faster."
If that's true, step four of the scientific method says we're ready to make a prediction
based on the hypothesis, so we can predict that dark-colored ice cream will melt faster
than light-colored ice cream. It's important to note that a hypothesis doesn't have to be
right. We learn just as much from proving a hypothesis wrong as we do from proving it right,
but a hypothesis does have to be testable and provide measurable results. Step five of the
scientific method tells us that if we want to test our prediction, we need to conduct an experiment.
Have you ever performed a science experiment? Maybe you've done one for a science fair or
just for fun? Experiments teach us so much about how the natural world works.
However, experiments aren't all fun and games, because there are different elements of an
experiment that must be included for the results to be accurate and valid. Science experiments
generally include an independent variable, dependent variable, control, and constants.
An independent variable is the part of the experiment the scientist changes or controls. The
dependent variable is the part of the experiment that reacts or depends on the independent
variable. The control is the base experiment scientists use for comparison against the other
trials of the experiment. A constant is the part or parts that don't change during the experiment.
What do you say we apply these new terms to our sample experiment? As you'll recall, we want to
know if the color of ice cream affects the time it takes to melt. We can perform this experiment by
placing one scoop of white ice cream in a bowl on the kitchen counter and timing how long it takes
to melt. This base experiment, the white-colored ice cream melting at room temperature, becomes the
control, and we will compare different outcomes to this control. Now, we want to see how long
it takes for other colors of ice cream to melt. We place one scoop of bright green ice cream,
one scoop of light pink-colored ice cream, and one scoop of dark brown-colored ice cream
in three separate bowls on the kitchen counter and time how long it takes each color to melt.
After repeating the experiment at least three times under the same conditions,
we find that color does affect ice cream's melting rate,
and since we changed the colors of the ice cream, color is the independent variable.
The amount of time it takes the ice cream to melt is the dependent variable, because it changes
based on the independent variable – the color of the ice cream. As you remember, a constant
must stay the same throughout the experiment. Some of the constants in this experiment are the brand
of ice cream; how frozen each color of ice cream was before scooping them; the amount of ice cream
used; the material, size, and shape of the bowl; the timer used; and the temperature of the room.
As you can see, a constant can be many different aspects of an experiment.
The evidence you collect at this step may be in support of your hypothesis,
or it may reject it. Either way, your experiment is a success, because it still provides valuable
data, even if the data is different from what you expected. The last step of the scientific
method is to reflect on your results, use them to guide your next steps, and share them. If your
hypothesis was supported, you might do additional tests to confirm it or revise it to be more
specific. If your hypothesis wasn't supported, you might come up with a new hypothesis.
A well-designed hypothesis and experiment will produce valuable results for you to share so that
others can learn from your effort. In science, this is often done through scientific journals,
or maybe you'll share yours with your friends and family so they know which color ice cream
to stay away from on a hot summer day. The same way you reviewed existing research on your topic
before you started your investigation, others may want to repeat your experiment
to see if they get the same results. After all, scientific results are only considered reliable
if they are repeatable. If other scientists can't repeat your results, they may suspect
bias or prejudice in your experiment. This is why good experimental design is so important.
As you can see, the scientific method is more than just a simple six-step method for performing
scientific investigations. When used properly, the scientific method is one of the most valuable
tools humans have ever created. It helps us solve everyday problems around the house and, at the
same time, helps us understand profound questions about the world and universe in which we live.
Well, that's our lesson for today. If you were following along, you now know that
the scientific method gives scientists a model to work through when trying to understand the world.
The scientific method has six basic steps: Make an observation, ask a scientific question,
form a testable hypothesis, make a prediction based on the hypothesis,
test the prediction, reflect on our results, and share them.
Hey, don't forget to check out the engaging games and thought-provoking resources related to this
lesson to prepare for our next lesson, where we'll explore science in action. And remember,
in space science as in life, you are out of this world! See you next time.