Hi everybody! My name is Miranda and
welcome to our first Science Alive lesson
all about the scientific method.
[Upbeat music]
The whole purpose of science is to explain
and understand the world around us, and
the scientific method is how we do that.
Now you might be thinking, what is the
scientific method?
Well... The scientific method is the steps
that scientists around the world use
when they conduct experiments.
The scientific method is made up of six
super-important steps. The first step of
the scientific method is all about
asking questions. In order to understand
something, we have to be curious about it.
This can be anything that you are unsure
of or that you're wondering about,
anything like that could be your question.
For example, if we wanted to know
something like "why doesn't the ocean
freeze?" that would be our question.
After we ask a question, we have to collect research on the topic. So what this means
is we find the information that's
already available to us from previously
conducted research, or just things that
we know because we've observed
situations. So going back to our example
on "why doesn't the ocean freeze?", we would
look up different resources online, ask
questions to our friends and family, and
see what we can come up with about why
we think the ocean doesn't freeze.
After going through research we can make a guess to what we think could be the
answer to our question. This is called a
hypothesis, which is just a fancy way of
saying an "educated guess of the answer
to our question". Since we can't see the
future, we have no idea if our guess is
right or wrong and that is totally okay.
Going back to our example on ocean water, we could say but the main difference
between ocean water and other water is
that there's salt in it. Our hypothesis
could be something like "if we add salt
to water, then our water won't freeze".
Now that we have a hypothesis, the next step is designing our experiment.
An experiment is a carefully designed way
to test the hypothesis and see if our
guess was right or wrong. In an
experiment, scientists such as ourselves
like to make sure only one thing is
being changed or tested so that our
results are clear, and only answering the
question that we asked.
After we get results, we have to analyze
them. Analyze is just a fancy word for
reading and understanding the results of
our test.
By analyzing the results that we get
from our experiment, we can find either
support for our hypothesis, or we can
prove that our hypothesis is false.
But we never ever ever say our hypothesis is 100% true or false. The reason we do this
is because in the future some other
scientists may create a different
experiment about the same hypothesis that can prove our hypothesis is actually
false, even if our experiment supported it.
After all of these things, we get to the
last step of the scientific method which
is our conclusion! Our conclusion is the
final statement that we make in the
final step of our scientific method.
This means a generalized statement that
we make about our hypothesis from our
results of our experiment, so that we can
share it with others. Okay. So I know that
was a lot of information, but now that we
know what the scientific method is, we
can use it! Time to get started with some
super-fun experiments. Today's experiments are all about acids and bases.
The supplies that we will be using are all
listed in the description box below,
in case you want to try this yourselves at
home. Just make sure that you have an
adult with you. In order to test whether
a solution is acidic or basic
we need something called an indicator. An indicator is something that we use to
determine whether a substance is acidic,
neutral, or basic. The indicator tells us
where the substance falls on a pH scale,
which is how scientists classify acidity.
A pH scale looks something like this.
Acids will be on the left, neutrals
will be in the middle, bases will be on the far right.
For today's experiment I'm going to show you how to make red (or purple) cabbage
indicator. If you don't have red cabbage
feel free to check the description box
below for some other natural indicators
that you might have around the house.
Our first step for making the red cabbage
indicator is cutting up our cabbage into
smaller pieces. You can use a knife or
your hands to do this step. So once we've
cut up our cabbage, we can put it into
our container and then I would recommend
going outside for this next part because
it can get kind of smelly inside. So once
you have your cabbage in your bowl, you
can pour your boiling water onto the
cabbage, and then stir it for two minutes
and then let it sit. and you just want to
make sure that the water is covering the cabbage.
Once it has sat for 20 minutes,
you can strain it through a strainer and
separate the cabbage from the purple
liquid. Then you want to just let that
sit in your second bowl and let it cool
completely before you can bottle it.
It can stay in your fridge for a few
days, or you can put it in the freezer.
Just make sure that you don't leave it
at room temperature because it can get
really smelly. Now that we have made our
indicator it's time to conduct the
experiment! Following the steps of the
scientific method, we are going to test
some substances and see whether they're
acidic or basic.
Now that we've made our hypotheses it's
time to start on our experiment. Since we
are using red cabbage indicator we know
that when it's purple it is neutral, when
it's an acid it turns pink, and when it's
in the presence of a base it turns blue.
In each of the cups I put something
different. In one I put baking soda and water.
In another I put dish soap and
water. The third cup had vinegar. Another
had just plain water, and the last one
had ginger ale but you can use any type
of pop you have at home. Now that we have all of our cups filled it is time to get started.
First let's test the pop. It's
an acid! Next let's try the vinegar.
Vinegar is an acid! How about dish soap? It's a base.
Baking soda. It's a base because it's blue! Plain water. Neutral. now that we've tested them
all and we know that water is neutral, we
can put water in the centre of our pH
scale at around 6. Because we used an
indicator we can line them up in order
based on the intensity of the colours. So
now that you have your completed pH
scale in front of you, you can go back to
your hypotheses and see if you are
correct, and then make your conclusions.
The next activity is all about antacids.
The purpose of antacids is to
neutralize the pH of the acid, meaning
the antacids are more basic than acidic. To test how antacids work, you can put
some acids such as vinegar, pop, or lemon
juice into containers with indicator
already in them. Then, try adding
different substances and see if you can
get the liquid in the cups from their
acidic pink to a neutral purple. When I
tried this I used Tums, milk, coffee and
water. As you can see from my results the
water and milk did not make the color
more purple. The coffee made my liquid a
deeper red meaning that it was more
acidic. However the Tums did turn my acid
into a purple, it just took a really long
time.
And there you have it! Thank you so
much for joining me in today's video. I
hope you enjoyed learning all about the
scientific method, and acids and bases
with me.
Can't wait to see you again soon! Bye!
