Hello everyone, my name is Felicie
and I am a scientist.
I work at the Lawrence
Livermore National Lab and today,
because I'm working from home these days like
many of us, I'm going to share a little
bit of my work and what I do with you.
I do a lot of experiments using lasers so
you've probably all heard about lasers
right? It's something that's used in a
lot of places in our daily lives. They're
used at the cash register to scan the
grocery prices. They're used to read CDs.
They're used for eye surgery.
They're used to cut through metals.
So lasers are
a really unique and powerful tool and
actually it stands for
and the L of laser stands for
light. So why not do a lot of cool
experiments that use light. So a laser, if
you've seen one, and you've probably seen
one. This is a laser pointer right here. A
laser pointer, if I take a piece of paper.
I'm gonna get closer here and then I
shine the laser onto a piece of paper,
you're gonna see a little red dot, okay?
And if I get my hand further away or the
laser further away from that piece of
paper, what you can see is that it just
stays a little dot right? And if I was to
shine this laser super far away in my
backyard well it would just still be a
tiny dot. Now if I do that with regular
white light like this one. This is a
convenient pen. It has both white light
and a laser. Well you can just see that
the blob of white light is going to get
bigger, Bigger and BIGGER and BIGGER
until it disappears because it's not
very intense. So if you see a light bulb,
you can see that it emits light that's
either white or yellow
and wherever you put yourself to look at
that light bulb you're still going to see
the light. A laser on the other hand is
only one color and we produce lights
that's possibly very intense because it
has the ability to put the light in one
direction. So at the Lawrence Livermore
Lab we have small lasers but we also
have very big ones and in fact we have
the biggest laser in the world. It's
called the
It's about the size of three football
fields and we use it to do a lot of
experiments. Among them we're trying to
achieve a fusion for our experiments.
Today I want you to grab a piece of
white paper like this one. A pitcher that
you can fill with water and an empty
glass. Any size and shape will work and I
want you to grab a pen so that you can
draw on the piece of paper. Let's try to
draw something in a piece of paper. Let's
say an arrow. I'm not a very good artist
but I'll try my best.
All right this'll be your best arrow.
Perfect. Now let's take our empty glass and
just pass it through I can see that
nothing happens you can still see
your arrow just roughly the same
colors and same size more or less. Okay.
Now let's take our picture
and fill the glass with water and if I
take this and put the glass
in front of the arrow
see what happens. All right.
We can explain this from a cool property of
light that is called refraction. So let
me go back to my home office and explain
refraction with a little bit of graphics.
So refraction is a property of light
and it can explain what we've just seen.
With our glass of water in our arrow
Normally when you have a ray of light it
propagates into a medium.
For example the
laser beam that I showed you earlier or
rays of sunshine propagate through air
and when they propagate like this they
propagate into a straight line however
when light encounters another
medium like water part of the light is
going to be reflected and then part of
the light is going to propagate into
water but it's not going to propagate in
the same direction it's going to
slightly change its direction. It's going
to be refracted. This is what refraction
is all about. It's when a ray of light
crosses another surface and as a result
slightly changes direction. So in the
case of air and water it's a specific
example but each medium
has what we call
an index of refraction we call that n so
let's go back to our example of air and
water. Air has an index of refraction of 1
and water as an index of refraction of
about 1.3 and so it's going to dictate
the ability of water to bend the
propagation of a ray of light and that
property applies to any material. If we
take another material say glass it also
has an index of refraction
and it's slightly higher than the index
of refraction of water so what it does
is that it's slightly bends the ray of
lights more than water would. If we take
our example with the glass of water well
this is really what happens. So I've
showed you a nice arrow that I have
drawn on the piece of paper and so if
you were to take rays of light that
depart from the arrow they just
propagate straight in air and then they
encountered the glass of water that I
heard in front of the arrow so what
happens in this case is that the rays of
light they are going to be refracted so
they're going to be bent and they're
going to need to be bent like this if
they're bent enough so if you have
enough water then each ray is going to
cross and then when they reach the other
side of the glass they'll go from water
to air. So they'll go from a medium that
has a high index of refraction to
another medium that has a low index of
refraction so they're going to be bent
the other way compared to what we've
seen earlier. That's what's going to
explain why the rays that you are seeing
at the beginning are flipped by passing
through that glass of water and so if
you're an observer placed at the end
of your glass of water it's going to
make it look like your arrow is pointing
backwards. All right everybody that's a
wrap that is it for the experiments.
I hope you had as much fun doing it as a
I did and I thought I could finish this
video by telling you a little bit about
how I got to become a scientist so I was
born and raised in France. That's where
I grew up and that's where I got all of
my education and I came to work at the
Livermore Lab only after my PhD.
So when I was little
I remember that I had a lot
of curiosity.
I like to ask questions to
my parents.
I like to read books, to look
at the stars using a telescope and I
think I remember that when I was a kid I
either wanted to be an astronaut or an
orthopedic surgeon so I am not doing
either of these jobs but at the time I
surely didn't know what lasers were and
that you could make a living working
with lasers and so I decided to study
physics in college and at some point I
was offered the opportunity to go to an
internship at the University of Central
Florida in Orlando. So I thought this was
really cool for two reasons. The first
one is that I was going to learn to
speak English because I didn't at the
time or not very well and the second
thing was UCF is close to Cape Canaveral
and I will be able to see a Space
Shuttle launch. So off I went.
I stayed there for two years.
I saw a space shuttle launch and one of
my professors there offered me an
internship where my job was to build a
laser and I got hooked immediately.
I loved this. I have loved building lasers.
I loved tweaking optics and that's when
I decided that I wanted to become a
laser scientist and use lasers for my
job. So I came back to France.
I did my PhD in physics using lasers
and after
that the professor who had offered me
an internship at UCF called me
when I was
about to graduate and said
"hey I moved to a place called
Lawrence Livermore Lab.
How about you come and
try to work in my
group and see if you like it?"
This was
12 years ago. I still haven't left the
lab. I have enjoyed my career there since
and so I think this tells one thing.
When you're in high school or when
you're studying you probably don't know
exactly what it's going to be like in
your job but you will meet
people. You will be given opportunities.
So my advice would be to try to keep
your eyes open and sometimes things
don't go according to plan and that's
fine but be open to new opportunities.
I never knew I would be a laser scientist.
I never knew I would work with lasers
but I'm enjoying it very much now.
If there was one thing that
I could tell to my high
school self, I would say sometimes it's
okay to fail.
You know, if you have bad
grades or if you're not happy with
something that you've done in
school, that's okay and this is the case
also in my job. Every mistake or failure
is an opportunity to learn something new
or something differently and it's not
because one day you have bad grade and
math or physics that you're not made for
that and also something I wished I knew
when I was in high school is don't
necessarily listen to what other people
think. What's important is that you
follow what you want to do and so if
somebody tells you "are you sure
science is really for you?" Well don't
listen. If you like science or if you
like something else, just go for it
and give it your best. So with that I
still have one more thing I want to
share with you and then we can say
goodbye. All right because I can't go
outside, I'm going to do indoor
biking and this is actually pretty cool.
I'm sure that a scientist is behind
this wonderful invention that allows you
to put your bike on machine and pedal
like if you were outside. So that's what
I've been doing and with that I'll go on my
ride and I'll say goodbye and I hope you
all stay healthy and you stay safe and
take care of yourself and then we'll get
all together through this but in the
meantime don't forget to do some good
science and learn about some cool
science. All right. Bye everybody!