Hello, I'm Jared. Welcome to Fun Science Demos! In part one of our video that we called
"The force of friction and our feet", we took a closer look at the bottom of our shoes
to see if we could get a better idea of how the force of friction is at work
on the bottom of our shoes. So here is my shoe and we are going to zoom in and take a
closer look at the patterns of lines on the bottom of my shoe. If we look closely at the
patterns and lines on the bottom of my shoe, it actually tells a really interesting story.
It seems that there's certain parts of the bottom of my shoe that are darker. Right here, this part
is darker and if I look at the back part of my shoe, there's some darker parts. They are darker
because they are worn down well. What is doing all that wearing down? Well, it is the force of
friction at work! If you look at the bottom of shoes, all different shoes, they have different
patterns and lines and we thought it would be a really neat design challenge to see if we could
make our own pattern of lines for the bottom of shoes, and see how the force of friction is at work
in our own patterns! We came up with very simple materials to use to make the bottom of our shoes
and for that we're going to just use school glue that's washable. It is important to use school
that's washable, because it is pliable and flexible when it dries, and some aluminum foil and a pencil
and that is it. We are going to start with a good size piece of aluminum foil. That is going to allow
us to fold it again and again and again, until we have something about this size. So here we go.
...and I am ready to go! Now my foil but I need to put it on a stack of paper or a folder or something
because it is going to be a lot easier to draw on the foil when it's sitting on top of something.
I am going to just start by drawing an outline of a shoe. It does not have to be perfect. In fact, you
could print out a template and have kids trace it. I am just free handing this and you can see
I have my outline of a shoe on my foil and now I'm just ready to start designing my pattern.
Now when making these you might actually want to make your first one totally smooth so that you can
compare it to other ones you make with different patterns and lines. Now it is time for the pattern.
What's interesting is you could actually use real shoes to get your ideas or you could be creative.
I could draw arcing lines, you don't want to press too hard that you tear the foil,
but hard enough that you're actually seeing the line imprint on the foil. We have zoomed in so you
can take a closer look at some of the patterns I'm going to draw. I could do a zigzag line.
I could draw a series of circles. Now what is interesting is I could actually use a compass or other tools
to help me draw those circles. I could take my time. I could draw a different shapes I could go squares
I could do a triangle in those squares. I could do stars. I could do any design that I think
looks cool, and might give the bottom of my shoe more friction. Now take a look at my design.
You can see I could choose to really fill in all the space and add a lot of different patterns and
lines. I could make it simple. That is the neat thing about this. Now we need to add the glue.
That is going to become the bottom of our shoe. so the next step is adding our glue.
Now there is different ways of doing this. I could use the container and just squirt it on.
I could dump a pile on and use my finger to smooth it out but you want to make sure it's thick enough so that
you have a really strong substance. You want to make sure it's thick enough so that you have a
really strong substance for the bottom of your shoe. I like to just use the glue bottle itself.
I hold it a little bit away from the foil. I like to go my outline over my outline first...
and now I just start filling it in, squeezing the glue out, the glue is going to flow right into place.
I take my time...
...and fill the entire bottom of my shoe in with glue if I want to I can use my finger
and coat it and cover it again. Rremember you don't want to take that glue too thin. Make
sure you have enough glue so that it's nice and strong. So I can do some experiments with it
when everything dries. This is what it should look like. Now it may take some time to dry. You might
want to use a hair dryer. You might want to blow on it, put it on a blowing vent in the classroom
just to speed up the process, and it's ready to peel. So it is all dry. You want to find an edge and
it might take a little bit of time to start your edge, and once I start it, we will zoom in so you can
see closer what this is going to look like coming off. So I am going to just pull slowly.
It should peel right off of the aluminum foil and take a look at that I have a really cool design
that I can test out. So here are three that we made up and what's interesting is just by feeling them,
I can feel the difference in friction. Here is the smooth one but if I run over the ones where it has
a bunch of patterns and lines. You can feel I am probably going to get more friction out of this one.
So we have our two designs the smooth one the one with all kinds of patterns and lines. Now it's time to measure.
Something we want to see which one of our shoe designs has the most friction. Now, we could use a spring
scale to measure the force of friction but we decided we were going to use something that was a lot simpler. We're using two identical
rubber bands. They have to be the same so we can really compare to see which one is using more friction. To make this work, I am going to
add some weight by picking two of the same shoes and putting them right on top of my shoe designs. I am going to line everything up, and
now I am going to pull on the rubber bands and see which one actually requires more friction to move. You can see this one is moving a whole
lot easier. I am stretching that rubber band and it just finally moved. Let us do that again and we can compare again. So take a look at how I
have this set up. I am pulling these rubber bands just so they are just ready to move and you can see this one is stretched a lot further.
That means there is more force of friction at work holding this in place. Let me talk a little bit more and you can
see I am really stretching this one out, because the force of friction is really at work on that one. If you have a spring scale,
another thing you can do is also measure with that spring scale have a little clip clip it on the bottom so I have something to grab put my
shoe on top hook. My spring scale on and now watch the spring scale we're going to zoom in so you can take a closer look at and
see the force of friction at work. Here we go. I am going to start pulling so watch our spring scale
it is not moving yet it is not moving yet almost to two up it's starting to move and it looks like
it is steady at one. My spring scale was reading one Newton because we measure the force of friction
in Newtons. The neat thing about this is that you can try different things different patterns
different lines even different glues try them out and see which one has the most friction at work
and then remember to try and measure that friction at work with either a spring scale or a rubber
band. If you want to learn more about friction and forces, check out our video description.
It is amazing to think that science is everywhere, even on the bottom of our feet. Thanks for watching!