everyone and welcome to science
alive. I'm Rosemary Body, and this is
Dr Laura safe. And does she
have a show for you today? So I want
you to observe. And I want you to listen
because you don't want to miss a thing. Thanks,
Rose. Marie, I'm so happy to be here on
science alive today. We're going to be covering Strand
H. The nature of science benchmarks s
C H 1.2 point one s C
H. 1.2 point two s c h
1.2 point four S c h. Three
point to point to an S C H
3.2 point four. In
other words, we're going to be covering scientific thinking and the
scientific method. When you follow the scientific method, you
always start with a question called the statement of the problem.
It's a question that needs to be solved by experimentation.
Today. Our statement of the problem is, does the shape
of the wand affect the shape of the bubble?
Well, before we can answer that question, we have to do some
research, some background information. That's a very
important step, because then we're going to make a hypothesis
but we need information first. In order to get some background
information, we could go to a lot of places. We can
look in encyclopedias.
We can look in special books like this book's about water
soap, Bubble magic and another book about water.
I can also look on the Internet, talk to people, other
scientists, and I can even do some science activities.
So let's get started. We're going to do some science activities toe, learn about
some water and bubbles. Water has many
properties. Water is a liquid, and like all liquids, it flows and
takes the shape of its container. This is water with
a little red food coloring in it so we can see it. So I'm gonna take our
water, and I'm gonna put
a drop of water on a piece of wax paper.
There's a nice big drop of water. Can we zoom in on that?
Look how that water bubbles up. There's a reason for that called
surface tension, which we're gonna learn about in a few minutes. But
first I want you to learn about cohesion and
cohesion is when molecules of a substance are attracted to
each other. I'm gonna take this toothpick, and I'm
going to drag the water with the toothpick and you'll see
that the water comes along. And
that's because of cohesion.
If I put two water droplets down,
the cohesion will allow me to bring the two drops
together. Like so.
So that's the property of water called cohesion. Now
we're gonna learn about surface tension.
Surface tension is created by the attraction of molecules in a liquid for each
other, especially at the surface of the liquid. Any molecule
in the liquid is attracted equally in all directions because it's completely
surrounded by other molecules. But the molecules on the surface or the
top of the liquid are exposed to air molecules on one side.
That means the liquid molecules on the surface of the liquid
are on lee, attracted by other molecules in the liquid,
especially on the sides and down into the liquid.
This causes a very tense situation, a
strain or tension at the surface of the liquid,
kind of like a tug of war. This tension
is called surface tension. Rose Marie, Could you come
help me a minute?
If we grab hold of each other and are pulling? That's almost like how the
molecules are being pulled in each other. Thanks, Rose Marie.
So now we're gonna look at a drop of water again.
And remember that Don't we saw
that? But water bubbles up because the surface tension of those
molecules pulling at each other are pulling the water
droplets down into the molecules down into the water and
on the surface. If we look over here
at a cup of water and this water cup is pretty full,
I'm gonna add more water to it and try
and make it so full that the water goes over the rim
and we'll see if we can do it without letting it spill.
You see how high that water is?
Now? I'm gonna add some paperclips in it,
and we're going to see if the water spills out of the cuff.
Here we go.
One, two,
three. And you can see that that dome of water
is getting higher
and higher as I put the paper clips in the
cup. And that's because the surface tension of water is so strong
and the attraction between the molecules is holding the water in
the cup. We're gonna do another experiment. So you can learn a little bit
more about surface tension. Did you ever
see a water bug walk on water?
They couldn't do that because they're not very heavy, but also because of the water
surface tension. So again, I'm gonna take a cup of
water, and I'm gonna fill it way up.
This time it doesn't have to get quite so full. And I'm gonna take a
needle and I'm going to try and
float this needle on the top of the cup.
Here we go. Okay. We've got to be very careful.
Look at that. There it is. The needle is floating on
top of the water because of the surface tension of the water.
Just like a water bug walks on water. That's a
pretty cool demonstration, isn't it? We're gonna do one last
one because surface tension is really important. In order to understand what
bubbles D'oh! So we're just gonna move that wand over and
right here I have a pan full of water. I'm going
to Sprinkle a little bit of baby powder gently on top of the water
so it floats,
okay. And again, that baby powders on
top of the water because of the surface tension of the water. And of course,
baby powder is not very heavy. Now I'm gonna use my eye dropper.
Get that colored water out of there,
clean it out a little bit so you can see that it's
just an empty eye dropper, and I'm gonna take
a drop of soap.
And let's see what happens when we put a drop of soap
into the water that has the baby powder flight
floating on the top. Ready? Here we go.
Watch it carefully.
Wow, You know what happened there?
Soap breaks, the surface tension
of water. In fact, soap gets around those water molecules
so they can't get back together. And that's why
soap is used to wash dishes. And that's why soap Little
has helps water make more bubbles because it reduces the
surface tension of the water. You need to know
one more thing before you could make your hypothesis
about the bubbles and about the ones. Because the
hypothesis is not a guess. It's an
educated guess, which means it's based on information. So I need to give you
one more piece of information, and that's about the
shapes, geometric shapes you see I have here
of all. Another name for a ball is called a
sphere, and a sphere is an
important shape because it's the geometric shape
that allows for the greatest volume the greatest amount of
space with the least amount of surface
tension. And don't forget surface tension makes bubbles.
Makes makes it easier for bubbles to form if we reduce the surface
tension. So now that we know that water has
cohesive properties, that water has a
very strong surface tension. Look at that dome
up kind of almost making a curve there,
and that a sphere is the
geometric shape that allows for the greatest volume with the least amount of
surface tension. We now have a lot of information that we
can use to make our hypothesis, And the
hypothesis, like we said, is an educated guess. It's a
prediction. It's based on information. So based on
everything we now know, let's make a hypothesis
about the shape of the wand in the shape of the bubble. I think
for our hypothesis today, we will say
that if a sphere is a geometric shape
with the greatest volume that provides the least amount of
surface tension then the shape
of the wand is not going to affect the shape of the bubble.
That's my hypothesis. You may have something else. You may think
something else from your experience and your information. And that's okay too.
You see, boys and girls Ah, hypothesis is just a prediction about
what we think is gonna happen. If we knew all the answers,
we wouldn't have to experiment. Also, we don't want to
change our answer if we're wrong. You see, we do
an experiment to collect data, to see if it supports our
hypothesis or if it doesn't support our hypothesis. In
fact, many of the inventions in the world have been
discovered because what scientists thought would happen did
not happen there. Hypothesis did not support or their data did not
support the hypothesis. So now that we have
our statement of the problem, does the shape of
the wand affect the shape of the bubble? And we did
our research. We have our background information
and we have our hypothesis. Does the shape of the
one affect the shape of the bubble? We're ready to
move on to the next phase of our experiment, which is
to gather our materials. So let's see what we
need for our materials.
We're certainly going to have to mix some bubble solution. So
let's see. We're going to
need some water. Okay?
We're going to need some soap.
And dawn makes wonderful bubbles, Don and joy,
I found from my experience, makes the best bubbles. But that could be
a different story for you also, I'm going to share a
secret with you if you add sugar
to your solution. Sugar helps make
good, strong bubbles.
So we have water we have done. We have
sugar. We need a measuring cup.
Sorry about that. He is our measuring cup for
amounts. And then we can mix our bubble solution
and boys and girls. When we mix our bubble solution, you want to mix it
ahead of time because when you mix it ahead of time and you let it
stand for a couple of days, it lasts a lot longer.
Gives gets stronger, nice, strong bubbles. I happen to have
here some bubble solution that I mixed the couple of days ago. And
that's where we got this bubble solution. So
Okay, so why don't we mix some bubble solution
and get it ready for when we start our experiment.
Here's a jug of water, which is
3/4 full. It's This is a gallon jug. This is a
full gallon. Are excuse me a gallon jug and we fill it
3/4 full with water. Then I'm going to
add a cup of sugar because, remember, sugar
makes our
bubbles stronger. And measuring is a very important part of
science and math. You have to measure carefully, so you have
the right amount of ingredients in your bubble solution.
So I'm gonna shake my cup a little bit, and
I'm going to get eye level so that I could make sure I have the right
amount of sugar. And then I'm gonna use another piece of
science equipment called a funnel to help me
pour the sugar into the jug.
That way I won't make a big mess, because if I make a big mess, I have to clean it
up. So in goes our sugar.
Okay. The next ingredient I need, of course, is
our detergent. And remember, we're gonna use dawn because I
have found, based on my experience, that dawn makes
great bubbles. I'm gonna put a cup of
dawn.
Now I'm gonna put it down.
And again. I want to make sure that I have the right amount.
Looks like I put a little too much in there, so I'm gonna pour a
little in here. Now,
I'm gonna put it down again, and I'm gonna
make sure you up. That's a cop. I'm gonna get my
funnel again so I don't spill, and I'm gonna
pour through the spout into the gallon so that we
have a good, strong bubble solution.
Okay? And I'm gonna add, I
think a little bit more water.
I can use my cup from over here.
So we have a full gallon of juice,
then I'm going to cover up my jug.
I'm gonna shake it up really well.
Kind of turned it upside down because it is kind of heavy. It's
important to let the sugar dissolve
completely. And
now I have to let my bubble solution
sit overnight before I can use it.
The longer it sits, the better it is. Boys and girls take a
look. I don't think I used anything really experience really
expensive. I used some dishwashing soap, and if you don't have dawn, you
can use something else. I used some water
and you can get it from the faucet. You don't have to buy water and
a measuring cup and then a little bit
of sugar. So it's not a real expensive
experiment, and I'm gonna let my bubble solution sit. Now, there are
other materials we're going to need for our science experiment and the other
materials gonna we're gonna use to make the wands. We're gonna make
all sorts of shapes ones. So now, before we
get into building are ones I think we're gonna have to do that next time.
Let's review what we've done today. We
started strand age with the scientific process.
We started our experiment with a question. Does the
shape of the wand affect the shape of the bubble? That's our
problem. Statement. Then we needed to learn some
information we needed to get some background information, do some
research so that we would be able to make a good
hypothesis. We learned a little bit about
water surface tension. We learned about some
cohesion with the water of droplets going
together, and we learned a
little bit about what soap does to water. and how a
sphere is the geometric shape or
structure that allows for the most volume in the least
with the least amount of surface tension. And then we made our
hypothesis. What we think is going to
happen and our hypothesis waas or is
that the shape of the wand will not affect the
shape of the bubble. We're going to have to test our
hypothesis, meaning we're gonna have to experiment in our next
episode to find out if that's what really happened.
So I'll see you next time on science alive.