hi i am jared. welcome to fun science demos. what person does not love a cheese ball? and what kid
has not taken a cheese ball, thrown it into the air, and tried to catch it in their mouth?
well, today we have a stem design challenge where we use simple
materials like cardboard tubes and rubber bands to make our own cheese ball launcher.
now, this launcher could launch all different kinds of things. we could launch cotton balls, we could
launch ping pong balls, we could launch goldfish. we decided to go with cheese balls because
we can get a giant vat of cheese balls and have plenty of things to launch. so let us start by
pulling this one apart so you can see how simple this is to make. to do that i am just going to pull
the rubber bands over the pencil and you will see my launcher slides apart into two pieces.
now, the one thing you need to notice is that one tube - my inner tube - has to be smaller
than the other so it can fit inside, but most cardboard tubes are the same size, so what do we
do with these? so how do i make one cardboard tube smaller than the other? i need a pair of scissors.
i am just going to cut right down the center of one of the tubes.
what that allows me to do is to shrink the diameter of that cardboard tube so it fits inside.
now all i need to do is tape this up and i have my inner tube ready to go. so now we
have our cardboard tube taped up but we want to be careful when i slide this in. if i make that inner
cardboard tube too small it will actually allow the cheese ball to get wedged in right between the two
tubes and then my launcher will not work. now keep in mind that these are paper towel tubes but toilet
paper tubes also would work. you would just have a shorter launcher, and you can see with this version
i just use smaller toilet paper tubes. now, the next step is to cover this end with tape so
the cheese ball does not fall through like this. that is not good. now the one thing we figured out
when we made our first version of this is that if you pull the tape too tight, the cheese ball
kind of wants to roll off, so you will notice i put a little bit of a dip in the tape, so now
it cradles the cheese ball perfectly. now the next thing we need to do is put in our pencil stop,
and we have some choices to figure out where we put that pencil stop. you willl notice on this design
i put the pencil stop right at the end of the inner chamber, but we have an interesting problem
happen when we do this. it is hard to grab. there is no handle. so how do we get around that? well,
here i just simply bent a paper clip that wrapped around, which allows me to pull back
i could also use a pipe cleaner. now i have my pipe cleaner wrapped around, and that gives me a handle,
but what we decided to do with this version is leave our tube a little bit long and
it is the perfect handle grip that really allows me to pull back on our cheese ball launcher. so what
i am going to do is slide this in, figure out how much of the tube i need to really get a firm grip,
and then figure my pencil stop has to go somewhere around there. now, we have another problem. if i am
going to use a hole punch to put a hole in my cardboard tube, my hole punch is only going to
be able to go up so far and that is really what limits me. that is why we have put it close to the
end here because i can use my hole punch to punch the hole. if i am going to use something
else to punch the hole i could use something like a sharpened pencil, or a screwdriver, but i want
to be careful that i am not stabbing through into my hand, so you always want to do this on a table.
make it safe. so we have our pieces assembled, you can see
they slide together. there is one other thing i have to think about before i
attach the energy source, and over time as this pencil slams into that cardboard tube
it is going to start to really bend it down, so i need to reinforce that with something like tape,
just so it makes this more sturdy, so you might want to wring some tape around that even put
some tape down inside, but just make sure it is nice and smooth, so that my inner cardboard tube slides
right through. now it is time to give our energy source something that is going to power our cheese
ball through the air. for that we are going to use rubber bands, and it is really up to you how many
rubber bands you use. we suggest you start with two rubber bands running down each side, and get
some measurements to see how far that cheese ball goes, and then you can start adding some rubber
bands to see if you can redesign your cheese ball launcher to make the cheese ball go even further!
so how do we attach the rubber bands? well, i need to put two slits on the top of my tube, and we are
going to zoom in, so you can take a closer look at how that is done. so we are zoomed in, so you can see
i really do not need to make slits that go all that far down, in fact it is hard to see so i will
pull this back, and you can see how the rubber band fits right in that slit. now it is safe to say that
if i tug on that rubber band the slit is going to open up, so i definitely need to go back over
this with some tape to make sure that does not rip out. now, do the same thing to the other side.
two quick slits to make a little cardboard tab, open that up, now all i have to do is tape this
closed, and i am almost ready to use my launcher. so, now we have our energy source attached and ready
to go. now, keep in mind the further back we stretch this rubber band, the more energy we are putting
into our launcher, so if i am using a shorter launcher and my rubber band does not get stretched
as far, it is not going to have as much energy. it kind of makes me think: i wonder what would happen
if we tried to make a really long launcher? we put a whole lot of energy into that rubber band!
i think that is our next build design, so let us see how this works. i am going to slide my inner tube in,
i am going to stretch one rubber band down, hold it, i am going to stretch the other rubber band,
and now i have a launcher that slides back and forth. i think we are ready to give it a shot, so
now we are ready to test fire. load your cheese ball, now i am going to launch it this way just
so we can see what kind of launch happens here, so hold it sideways pull it back: three, two, one!
that cheese ball flew across the room! let us try another launch. load up the cheese ball, lower, angle,
three, two, one, fire! what is so cool about this is we could use our cheese ball launcher to do all kinds
of things, and collect all kinds of measurements. maybe we put a target, and our goal is to try and
see if we can get it into that target - a waste basket, a trash can, a laundry basket, and if we are
not shooting it far enough we are going to have to figure out how do we increase our energy source...?
maybe our target is up high, like a basketball net, and we are trying to make a basket, and if we are
not launching high enough, we have to figure out our launch angle. maybe we could actually track
the launch angle of our cheese ball launcher, and seeing if we are launching it at 90 degrees, how
high it can go! we take a trip outside, and measure how high our cheese ball launches into the air!
there are so many things we can do. the other thing i want to point out is you can see we have a design
flaw. my launch is already starting to break down, and that is normal, and it is going to happen
and what we need to do as scientists is figure out how do we go back and redesign this to reinforce
this, and make this stronger? this is the weakest part of my launcher, i have to fix that and make it
better. at funsciencedemos we are always trying to redesign our ideas to figure out how to make them
better. in fact, if you can come up with a better way to reinforce this end, put it in the comment
section. there are so many things we can do with our cheese ball launcher, in this case you can see
i have two rubber bands attached, well i added two extra rubber bands for more energy. we can
talk about designing a new handle for our cheese ball launcher, and see if we can design something
that is easier to use. best of all we can also talk about shooting more than one cheese ball at a time!
i think it is fitting that we try and load up our cheese ball launcher with as many cheese
balls and see what happens when we try to launch them. if you want to learn some more stem design
challenge ideas, or if you want to learn more about forces in motion, check out our youtube channel
funsciencedemos. science is so cool! especially when you get to launch something! three, two, one!