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so my favorite class in high school was physics
they open my eyes to the facts
that we can understand and predict so
much of the everyday world around us
using math and equations so today I want
to revisit the classic high school
physics egg drop competition where you
have to build some sort of contraption
around an egg to make sure it doesn't
crack when it hits the ground originally
I wanted to do a bunch of research and
testing to find the single best way to
win the competition every time but what
I found out with that each competition
sort of has different rules in some
you're not allowed to use popcorn or
parachutes and in others you win if your
contraption is the smallest or the
lightest or both so i'm going to show
you five super easy options and then
we'll talk about why each one works
let's go crack some eggs
okay so let's start with the popcorn
ball the basic principles that you put
your egg in the middle of a box that
contains some kind of cushioning
materials such as bubble wrap or packing
peanuts or popcorn personally I think
this one is the most boring but it works
and that's why every shipping company
ever shipped this way i'm using a ball
here because it's more weight efficient
in a box where you have unnecessary
cushioning in the corners plus the
stretchiness of the ball will help
absorb assembly energy
the moment of truth and we have an
intact egg before I show you the other
four ideas let's talk about the science
behind landing with an uncracked egg so
the starter you dropped your egg is up
high and it's stationary so it has
potential energy which is the energy
associated with height so these red
blocks represent the potential energy
and the higher I go the more blocks of
energy I start and then as the egg fall
that potential energy is converted to
kinetic energy which is the energy of
speed so you start up high and every
single block is over here as potential
energy but as you start to fall and fall
faster and faster every single block
comes over here is kinetic energy or
speed and now your egg is about to
impact the ground and have all this
energy in the form of speed that got to
go somewhere now this broom represents
the standing energy that holds an
eggshell together it makes it hard so
the way to think about this is when your
egg hits the ground do you introduce
more energy than the binding energy of
the molecule holding the hard eggshell
together at any point you're going to
break at that point so the question that
becomes what can we do to keep our
blocks below the broom because simply
put below the broom your egg is safe
anything above the broom and your egg is
busted well there's two things we can do
the first is that we can make this pile
of green blocks not as tall this is why
no matter what your contraption is to
protect the egg if your rules allow it
you should make a parachute the bigger
the better and it does not have to be
fancy this is like old-school army guys
style just cut up
bag little bit of string little bit of
tape and just looking at this you can
see the difference a parachute could
make so the second thing you can do is
not to remove any green blocks by
reducing your speed but to spread them
out so if we say left to right as our
time axis the more we could stretch out
this impact event the more we can lower
that high energy spike and this is a
cool way to think about any two objects
impacted the longer the duration of the
impact the more you can spread out that
force so stuff doesn't break so for
example this is the point of car air
bags instead of your head hitting the
steering wheel and stopping near
instantaneously it stretches out the
impact force overtime so you don't get a
quick spite that exceeds the broom line
for your skull this is exactly why long
jumpers prefer to land it's sand and not
on asphalt and why parkour runners will
always roll after a big jump it's all
about defusing the force over a longer
period of time so what does that mean
for our egg contraptions it surely is
something to keep in mind because it can
make it more intuitive for example to
see why putting your egg in the middle
of a jar of peanut butter which is a
popular and not a very good idea isn't
as good as putting your egg in the
middle of a popcorn ball okay back to
the bridge
you
so a lot of people like to build
contraptions out of straws and in some
competitions that's all you have to work
with how you configure your straws
depends a little bit on how stiff they
are the good folks at wendys have fairly
stiff straws which means I didn't have
to use quite as many so my idea was to
take six like three inch long straws and
build a regular triangular pyramid and
then put the egg in the middle and then
I took two of the Wendy straws and join
them together to sort of make a mega
straw and I use this wide tape to help
prevent it from buckling and then I made
six of those mega straws and simply
taped one to each edge of the pyramid so
the main point here is that there are no
straws pointing directly at the egg when
it impacts the ground the force goes up
the stiffness path through the straw I
saw a ton of examples online where the
straw was actually pointed at the a we
could create a puncture load in our case
we have this pyramid so all the loads
path next to the egg so you don't get
that primary impact three two one so
you'll notice we've got a couple of
broken pieces but that's okay because it
took energy to make those breaks and
that sort of protect the shell of the
egg and receiving that energy so success
ok so our egg finally broke but it took
about 20 tries and you can see there's a
lot of busted straws here all in all it
was pretty resilient yeah
so this one is a throwback to my NASA
roots in 2004 the emmy our Rovers landed
on Mars using giant airbags and even
though Mars has one-third the gravity of
Earth I figured it would still work I
started by cushioning the egg in four
little balloons that I barely filled up
and then I blew up bigger balloons and
then just tied it all together with some
string and tape and then if there's any
gaps in coverage you can just tape a
balloon directly to the stream you just
tied around in addition to the balloons
extending the impact time this design
benefits from a large cross-sectional
area relative to his weight so in a
sense it becomes its own parachute of
course if your rules allow it you should
still throw an additional parachute on
it anyways stop it from
I'm 2012 we landed another rover on Mars
called curiosity but this one was too
big to use airbags so we had to have a
power to send pretty much like a jet
pack so I wanted to pay tribute to
curiosity I got to work on her for seven
years and at first I was thinking like
model rocket but without gyroscopes and
control algorithms things can get pretty
unsafe pretty quickly so I thought of
this idea where I use balloons that
could deflate and then they would
provide upward thrust like before
landing but it now and as ridiculous as
this might seem it's actually not a
violation for most rules because you're
not touching it once you've released it
the fact is most competitions are using
rules that were written before you could
go on amazon and buy a toy drone for
less time 50 bucks
intact it I save this one for lassence
I've never seen anyone do it and it's
probably my favorite in terms of its
simplicity but you want to buy fewer
balloons and you need and then just pop
them until you get to the point where
you're just under neutrally buoyant and
you can see at the bottom I've just got
this little protector of the egg you
don't have to get fancy but I use those
little animal balloons that it seems to
work pretty good this one weighs in at a
couple ounces so it is a strong option
if your competition favors lighter
contraptions
so which one is the best again it sort
of depends on the rules of your
competition in some cases being smallest
gets you the most points so I'm thinking
in airwolf all the way if being like
wait is the most important then go with
the helium up house method and if you're
Angus needs to survive then you can pick
any one of these but the most important
part is to have fun and experiment and
learn something and then to dominate
your competition yeah you guys are good
no that's all right it's all right and
now you're on YouTube thanks for
watching if you learn something or if
you didn't learn something or if you're
a mammal then you should subscribe is
your blood warm you got a four-chambered
heart welcome aboard
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1st place Egg Drop project ideas- using SCIENCE

283 タグ追加 保存
huong 2017 年 10 月 9 日 に公開
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