everybody its norm from Tested and Kishore from tested and Kishore we are
thrilled so present with you new series demonstrating some great things with
science yeah there's amazing demonstrations that
you can do that showcase all of the fundamental principles of chemistry
physics biology they're all well within reach you remember those demos that you
used to see in high school yeah it's like magic it's nice to come in make
something explode basically Heisenberg from Breaking Bad so we're hoping to
show some of those for you over the course of this series and a little bit
of behind the process to put these together because they're oftentimes
really simple endeavors with really wonderful outputs
well we're privileged to have with us Zeek cos over from the Exploratorium
which is a great institution in San Francisco first science museums it's one
of the preeminent science museums in all of the world and it's a museum of
science art and human perception they maintained a library of all of these
science activities that you can do at home with your kids and at the same time
they train a whole host of teachers on how to do and teach better science in
the classroom walls you're going to chat with Zeek and please enjoy this simple
feat of science
welcome Zeke Zeke is a teacher at the Exploratorium which is a Museum of
science art and human perception and you've brought something for us to
experiment with today what are we looking at here so this is a vacuum
cannon cannon yeah that's okay the the origin of the vacuum cannon was that I
was a high school teacher for many years and the school wouldn't buy me a pool
table for my classroom I was taught physics and there's all sorts of cool
physics that you can do with a pool table but they wouldn't get me one and
when I asked them why they wouldn't get me one it wasn't that it was too
expensive or anything they said they were afraid that the kids would throw
the pool balls at each other or hate each other with the pool cubes and I'm
like what and there is a note you can't have one and then a couple of years
later they bought the kids a ping-pong table because ping pong tables are safe
because the ponds are safe right you can throw you can throw a ping pong ball at
someone pretty much as hard as you'd like and it won't hurt them like even if
you like give it the biggest slam you got it won't hurt him buy and the reason
is is that the ping pong ball for its size has a lot of air resistance they're
about two and a half grams and they're fairly large for two and a half grams so
the wind resistance slows them down super fast so like even if you were like
hit it at sixty miles an hour by the time I gets the other side of the table
it's only gone in like ten miles an hour so it slows down so much that you can't
hurt anyone with it and so that's why they got them at ping pong - so is there
a way to speed up a ping pong well so the if the problem with a ping pong ball
is that the air resistance slows it down so much then the solution is getting rid
of the air and that's why this is a vacuum cannon so what we have here is a
vacuum pump and I'm going to draw the air out of the tube and this is just a
PVC tube yeah this is a clear PVC let me set it up so we can put the ping-pong
ball into the tube like this roll it to the end and then we'll seal up the
ping-pong ball with some mylar this is the
stuff they used for emergency blankets don't tell anyone at the Exploratorium
that I stole their make you think they might learn about this somehow oh this
isn't going out to anyone I'm sure and then we need a target and we'll use this
can and then I can seal up this other side down here as well and how tight of
a fit is the ball in this too so what's really lucky is that this tube
is about 41 millimeters on the inside and the ping pong ball is 40 millimeters
so it's a very tight fit on the inside of the tube so that it just barely fits
down the tube anymore it would get stuck any less and then wouldn't make it as
tight a fit so you said the word cannon which to me imparts lots of energy is
gonna hit that yeah can so what's gonna happen is I'm going to take the air out
of the tube and then I'm gonna puncture the end of the tube and air is gonna
rush in so air pressure is about 14 and a half pounds per square inch and the
tube is about three square inches on the inside so about forty-five pounds of
force is gonna push on two and a half grams of ping pong ball you're mixing
weights but we took that it's okay yeah and so it's gonna push on the ping pong
ball and the ball is gonna get shoved forward now normally if you try to push
a ping pong ball really hard it can't go very fast because of air resistance but
there's no air or very little air on the front side of the ping pong ball so it
can be pushed incredibly hard and you can fly down to the end of the tube and
if everything goes according to plan it can be going 500 miles an hour by the
time it gets to the end 500 miles an hour that's like speed of sound level
yeah we're getting close to the speed of sound well I'm gonna get out of the way
because speed of sound sounds really fast and I'm really close to the cocaine
yeah no and let you run the experiment yeah so it's it's very loud so I'm going
to put on some earmuffs
and it takes about 30 seconds for it to pump completely down so now we're
pumping it down pulling me out and then I'm gonna close this valve so that when
the air rushes in it doesn't go into the vacuum pump all right let's count this
down three two one
whoa so here's our friendly ping-pong ball that's now been cleaved in half mmm
they don't make them like they used to but more importantly let's take a peek
outside can this wonderful hole is now dramatically in the can so this hit it
with with 500 miles an hour coming out of this thing right and it's so there's
basically a perfect vacuum and all that hits it does any air ever get around the
ball that's right so a little bit gets in front so the air is it's rushing down
a little bit the air can get past the ping-pong ball so there's a limit to how
long you can make the tube because as the air is getting in front of the
ping-pong ball then the ping-pong balls can be slowed down by that air in front
of it and then what the ends use this mylar which you use a heating blanket
I've seen it done other times with packing tape can you do that so packing
tape works pretty well but you need to get the extra wide time which is a
little hardest to come by and every so often the the the material gets sucked
down the tube because he didn't hold it well enough at the end and if that
happens to packing tape it is a bear to get that out because it sticks to the
inside where it's the mylar you need to blow it on the end you'll blow the mylar
back out oh this is fantastic I see you have a blast shield up but how important
is the blast shield to for safety I mean I I mean it looked like shards of this
was coming off so we're important to have yeah you need the you need some
sort of a shield you can get pieces of polycarbonate that's a hardware store
they're very sturdy you just need to make sure
clamp them down into place so here is a simple half-day project to almost break
the speed of sound so to prove all those people wrong that ping Kong's can't be
harmful exactly thanks so much the four people that want
more information about you and the Exploratorium where should they go they
can go to WWE explore Toria media or they can come down and visit us at Pier
15 and the Embarcadero in San Francisco and the Exploratorium has a number of
different activities online that you can do at home this is just a taste
thanks so much see thank you very much orcish or destroying soda cans with ping
pong balls it's amazing the power that even something like a ping-pong ball can
have when you remove air resistance to it I couldn't believe that it could get
up near the speed of sound right the sound is something you associate with
jet aircraft and it's something that you know you need to crating with a vacuum
its atmosphere or taking as much atmosphere pushing it through that tube
smashing through you know what else was surprising about it is the materials
that went into this project we're talking about PVC pipe talking about a
little bit of of putty and some plumbing fittings it's not super complicated
materials that went into it demonstrate one of the fundamental
principles in all of physics air resistance and I'm still blown away that
I guess you can really do some damage with a ping-pong ball awesome well we'll
be back with more simple feats of science with Kishore and Zeke so please
subscribe to our youtube channel like this video and leave your comments below
and we'll see you next time
you