hey guys it's jason latimer the world champion of magic and today
we're going to learn about center of mass and balance and my buddies ralph
macho and billy zabka from karate kid and cobra kai are on the show to help us
with some home experiments so that we can show you how to be a
balancing master with objects you can find around the house
welcome to impossible science
so what is the center of mass i'm so happy you asked first let's
define mass mass is the amount of matter or
substance that makes up an object meaning the center of mass well that's
where an object's mass is balanced in all directions for example take a solid
wooden baseball bat now imagine if we could tie a magic
string onto the center of mass in this bat that would mean that if we
could suspend the bat from just that point it will not want to tilt or rotate
in any direction that means we could leave it in
horizontal position and it would stay that way
we could leave it in a vertical position it would stay that way in fact
as long as that string is timed to the center of mass it would stay perfectly
balanced in any angle we tilt it or twist that
back so if you ever wanted to balance an
object well all we'd have to do is support it
directly above or directly below the object's center of mass now the
center of mass for a symmetrical object that's filled with all the same stuff
well that's pretty easy to guess where it's going to be like the center of mass
for a bowling ball is in the exact center of the ball but
what about an irregular shape home experiment time grab a broom which
is an irregular shape place your fingers on each side and
slowly bring your hands together and you'll notice that only one side
starts sliding down and then all of a sudden it starts
teetering back and forth as the broom helps you find its balancing point
and it's not the center of the object it's the center of its mass
but we can see the difference here we can see how the mass has been
distributed differently but what if we couldn't see
how the mass is distributed on an object well then we can make that object
balance in an impossible way and to prove it i've got the kings of
balance on the show from karate kid and cobra kai i've got ralph macchio
and billy zabka online to show us how to take normal items
and balance them in impossible ways thanks for joining me guys
ralph you're going to be going up first grab a couple of cups all right
and you're neither gonna grab a bill all right what you're gonna do is you're
gonna fold it on its ridge just about a third down oh
just on it's about a third down okay down and then you're gonna fold it up
from the bottom a third so now you're gonna be looking
like this so that looks something all right all
right and we're going to place it on the cups like this
all right very well done great ralph how did you do that the
first time i'm amazing in this case we know where
the center of mass is when we look at a bill we we
think it's uniform we think everything like that so i want you to grab one cup
all right and we're going to slowly pull it off to the side wait
what okay okay so i'm going to do that and there's
there's no average and it's not yeah that's what's happening
you're no abracadabra but there is a secret
see what happens is when somebody looks at a bill we think
that everything is uniform we think that the bill
is the same all the way through and honestly
because of some of the inc it may not be perfectly balanced
but when you think of something being uniform you we call
the center of a uniform object you call that a centroid and most people feel
that the geometric center of an object has to be the center of
mass all right that's not true if we add an object this dollar bill
trick costs 1.25 gotcha okay so that's so you're tucking
that in there so yeah so grab the quarter yes all you
have to do to change the center of mass in front of
your friends is to put a quarter behind the bill
then when i folded it i folded it into the bill
right so that's why it happened so now when you put it up here the center of
mass is actually over here still being supported so when you pull
that out look at that ralph you're a magician
magic no it's impossible science no you cannot
you can actually take it to your friends you don't even need cups to do this you
can actually fold it if you're out and you're
with your friends and you want to do this you fold it like this place it on
your thumbs right you can pull one thumb away that's
so cool that's so cool you got it almost yeah all right now
here's the best part with the hand that's still touching the
bill grab the belt turn your hand over let it drop and drop
out and give him the bill
i'm gonna have some homework i love this that's fantastic
all right now billy in this one we're going to use a pencil
and we're going to find the center of mass on a pencil take a pencil
all right take a paper clip if you would or in this case a safety pin and we're
going to place it in right here now by adding this safety pin
we've actually changed the center of mass we've added mass to the object
and if i hold it just from right there i can get it to balance
like that but wait wait wait whoa whoa whoa whoa that's not working get out of
town okay ah
this is exciting and totally frustrating at the same time
all right i need i need i need to understand this principle
here we go there you go
okay it's like the crane kick yeah right it really works it really really works
so why it's amazing that's doing that and it's still it's kind of moving but
it's still balancing in this case this really doesn't do much
this doesn't no it's not even the hole in the table is it stuck in okay
no but that's a good question that would totally work ralph but in this case we
weren't trying to manipulate the center of mass so rather than just
make this a pencil i've moved the center of mass
by adding to the base of it i ended up putting some weight you can build these
at home and i'm going to show everybody at home how to make these
so you can balance anything but in this case i've moved the center of mass
below the object right right hanging on that point that's awesome jason but i
didn't even have to add that weight yeah yeah
i'm just making a balance like that that's an impossible science in itself
oh hey wait no check it out actually yeah i had time to i figured that out
well you know i was like what could this use i thought it needs a washer and a
piece of wire i thought of that real fast so there it
is anyway so thanks guys so much for helping us to
find the center of mass to create balance with our random objects from
around the house so now that you know this you can go and
use the techniques from the pencil with your toothbrush or a box and change the
center of mass to actually balance items around the
house and you can get anything to work what awesome a good first pencil card
trick and a dollar bill amazing that's
incredible okay so now we know that any object will
balance as long as its center of mass is being supported from directly below
or being suspended from directly above and if we really want to blow everyone's
minds well we just have to secretly move the center of mass from where people
think it would be washers underneath the pencil was a
great idea because the center of mass is directly below the point of support
underneath the table and the quarter in the bill well the
quarter was so much heavier than the bill
that the quarter moved the center of mass all the way to one side
so look around the house you might be able to find some empty items that you
can put stuff in to move the center of mass
and have fun with it
let's check it out a quarter
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