Hello, my name is Dr. Leland Ellison and I am a computational physicist at
Lawrence Livermore National Lab. What does that mean? In short it means that I
get to use the second largest computer in the world to simulate what happens at
the number one largest laser facility. In this video I also have two science
demonstrations for you. In the first one I'll be teaching you a cool little
physics trick for telling whether or not an egg has been a hard boiled without
cracking it open and in the second demonstration we will be super cooling
water. We'll be taking it just below its freezing point and then initiating the
crystallization process all at once. It's a pretty remarkable effect. First
demonstration will teach you a handy trick for telling whether or not an egg
has been hard-boiled. There I have an assortment of fresh not boiled at all
eggs. Here are a couple eggs in the process getting hardboiled on their way
to becoming a delicious and nutritious treat and there is the cat.
So after 10 minutes of boiling. leaving the eggs to cool down for a little while,
and foolishly leaving the finished product unattended on the counter for 7
minutes, I'm ready for my snack. Now as everyone knows the proper way to eat
hardboiled leg is with a mayonnaise. I like to just apply it straight on the shell
on the outside. I find that leaving the shell on gives me a nice crunch.
We need a pinch of salt and a little crack of pepper.
That's not hard-boiled. So we've learned a difficult lesson today so what could
we have done to prevent such a CAT-astrophic accident from taking
place. From the outside, it is extremely difficult to tell
whether an egg has been hardboiled or not. They look
pretty much the same. Same weight. No mass escaped. If we cooled it down after we cooked
them and then they are both gonna be cold but here's a cool trick. Here's an egg. I won't
tell you which one it is. Let's see what happens when we spin it. Spins remarkably
well. On the other hand let's try egg number two. Didn't spin so well. Let's try them
both up on their end. Spins quite a bit. Almost instantaneously stops
Take a minute and think to yourself which of these do you think is hard-boiled and which
one is not. So imagine that you're a soft yolk - nice, round, heavy, dense piece of
mass - sitting inside the egg. As you get spun around you're gonna slosh back and
forth. You're gonna change what position you're in. It's that sloshing that makes the
spinning so irregular in a fresh egg. One that does not spin as well is not hard boiled.
Meanwhile with the hard-boiled egg the yolk has been condensed and congealed into a
solid matter. It stays in the same spot all the time. When we give it a spin
it just keeps right on going. So I like to think that today we learned that every
egg should be spun very aggressively before you venture on eating it especially
if you're going to bite through the shell.
For this demonstration, we need a couple of household items.
Here I have some bottled water. It came from the store. It needs to be very pure. I also
have some tap water. You know it's tap because it says tap on it. Less pure and
it's gonna help us tell when the other ones might be super cool. I also have
some sea salt (nice and chunky) and a large vessel filled with ice. Homemade.
Fresh from the freezer ice and I have a jug of water. Good old tap water.
So in this demonstration I'm going to be super
cooling water. That means we take water and
cool it down below its normal freezing point - 32 degrees Fahrenheit - and if the water is
extremely pure then we can get it that cold without forming that crystalline
solid ice structure but if we give it a good smack we can initiate that
crystallization process all at once and it's a pretty interesting effect.
So let's get started.
And somewhere in my house I have a thermometer where we can monitor the
temperature of all this.
Peel away some of the ice to see if my control tap water bottle has
started to crystallize yet. Doesn't look like it so let's keep waiting. So let's keep waiting.
Atticus is getting bored. Very sleepy. So my ice bath started to warm up the
water was getting to be 28 29 degrees and I didn't see any signs of freezing
so what I've actually done is taken them out and just put them in the freezer I
don't think they were gonna freeze in the ice bath as long as they were kinda
at the same temperature when I put them in the freezer here I should be able to
tell when the pure water is super cooled based on when the tap water bottle gets
frozen, so let's wait and see.
all right they've been in the freezer
for about an hour after the ice bath and would you look at that one of them over
on the right here is rock solid and the other one is not
and now let's see if we can get out our pure water one without initiating
crystallization process
I'm really excited I've never tried this before let's see still in the liquid
state air bubble in there somewhere there that's looking around okay so what
I'm gonna do next doesn't seem too sensitive I'm gonna
give it a good whack and see if we can kick off that crystallization process.
You ready? Make sure we get a good view.
Okay. Ready.
Three, two, one.
Oh and that is wicked cool. Oh man that's awesome.
Wow so it got seeded up by the cap and you
could just watch that crystal structure form around the outside it's not know
about you I've learned a lot to me I've learned that you should never bite into
an egg at least without spitting adversity I learned that the cat does a
crook who likes to switch around my hard-boiled eggs with the fresh ones and
I also learned a lot about the super clean water demo I tried it first in the
ice bath that was the first instructions I read
and they had some guidelines about how long it would take if you got it to a
certain temperature I think that was a bit difficult depending on the water you
start with the vessel it's in I think it's gonna take different amounts of
times I ended up using all of the salt in the house sorry Kelsey and it still
didn't get it to freeze so the freezer was better having a control bottle I've
had tap water it was a really helpful tip things I'd encourage you to think
about when trying this at home is to make sure that the two waters are
starting at the same temperature if you fill it with cold tap water and then you
have a room-temperature store-bought water bottle and you stick those in the
freezer it might not be a good indication of super cooling when your
tap water freezes I also think it's important to make sure that the same
bottle you want to be trying to freeze the same volume of water and have the
same surface to volume ratio for the cool I thought that the effect was
really worth trying at home without it's very neat some might even say it was
so now that you've heard how exciting it can be to be a physicist some of you
might be wondering what it takes to go into a career insights so there is a lot
of school involved I went through 28 grades which means that after I finished
high school I went to undergrad at the University of Colorado in Boulder for
you and that's where I got really excited about plasma physics and fusion
energy I had a really fantastic mentor there who taught me a lot in his
research lab and got me excited to head that direction then I went to graduate
school at the Princeton Plasma Physics lab for six years so graduate school
isn't really like the classroom school that you guys are familiar with it
involves a little bit of classroom work but it's mostly doing research so I
spent six years learning physics there and I finished my PhD and went on to
Lawrence Livan if you liked this video please check out the learning with
Leland YouTube series on Lawrence Livermore National Labs webpage you can
see me do all sorts of fun things like have swimming caps dropped on my head
and try to feed my heart donuts see you next time and that got me really excited
to keep pursuing that and my graduate school I guess is attacking a lizard
up into his tail it's like this is my new favorite testing starting point okay