Transcript for NASA Connect - Rocket to The Stars

Hey, hey, hey!

I'm Kenan Thompson.

But I play Fat Albert in
the live-action film based

on Bill Cosby's hit show.

On this episode of NASA Connect,

you'll learn about the science
concepts of work and energy.

You will also see how
we can use algebra

to help explain both concepts.

NASA engineers and scientists
will introduce you to exciting

and innovative space propulsion
technologies of the future.

And in your classroom, you'll
apply your math and science skills

by conducting a really
cool hands-on activity.

So stay tuned as host
Jennifer Pulley takes you

on another exciting
episode of NASA Connect:

"Rocket to the Stars."

Hi, I'm Jennifer Pulley,
and welcome to NASA Connect,

the show that connects you to math,

science, technology, and NASA.

Imagine it's the year 2040.

You and a team of
international scientists are part

of the exploration crew
that will begin construction

of the first human base on Mars.

You are laying the groundwork for
the next generation of explorers

to explore Mars and beyond.

It's not an easy task, but
you are up to the challenge.

All your years of
schooling, training,

and hard work have
finally paid off.

Does it sound like
a fantasy to you?

Actually, it's not.

NASA is ready to make the next step

to exploring the solar
system and beyond.

And they need your help.

NASA is looking for bright
young engineers, scientists,

and researchers who
will make the new vision

for space exploration a reality.

For you, it starts right
now, in the classroom.

Now, during the course of this
program, you will be asked

to answer several
inquiry-based questions.

After the questions
appear on the screen,

your teacher will pause the
program to allow you time to answer

and discuss the questions.

This is your time to explore
and become critical thinkers.

Students, working in
groups, take a few minutes

to answer the following the
questions: One, what comes to mind

when you think of work?

Two, how are work
and energy related?

Three, what are some
forms of energy?

Briefly describe them and
give examples of each.

It is now time to pause the
program and answer the questions.

So, guys, how did you
do with the questions?

Great job.

Okay, let's get started.

So what is work?

Well, most people would say they
are working when they do anything

that requires a physical...or
a mental effort.

Now, in scientific terms,
work is the use of force

to move an object
a certain distance.

More specifically, to
do work on an object,

some part of the force you exert
must be in the same direction

as the object's motion.

Let's look at the
following two examples.

On the left side,
Norbert is lifting a stack

of textbooks from the floor.

And on the right side, he is
carrying the stack of textbooks.

Note the direction of the applied
force and motion for each example.

In which example is
Norbert actually doing work?

If you said the left
side, you are correct.

Why isn't Norbert doing work
in the example on the right?

Well, because no part
of the applied force is

in the same direction
as the object's motion.

When the force is in the
same direction as the motion,

we can determine the amount of
work being done on an object

by multiplying force
times distance.

What are the units for work?

You know that force
is measured in newtons

and distance can be
measured in meters.

The product of a force measured in
newtons and the distance measured

in meters is a measurement called
a newton-meter, or the joule.

The joule is the standard
unit used to measure work.

1 joule of work is
done when a force

of 1 newton moves
an object 1 meter.

Do you have any idea how
much a joule of work is?

I know. Let's take an apple,
which weighs about 1 newton.

Now, if you lift the apple
from the floor to your waist,

which is about 1 meter, you do
1 joule of work on the apple.

But what happens if I
want to lift 100 apples?

For me, that would
take a lot of force,

and I don't think I have
enough energy to do that.

Let's go back to our
example with the apple.

Now, I easily have enough energy
to lift this apple from the floor

to my waist, and I know I'm doing
work on the apple as I lift it.

So there must be a relationship
between work and energy, right?

When I lifted the apple from
the floor, I caused a change.

In this case, the change is
in the position of the apple.

An object that has energy has
the ability to cause change

or the ability to do work.

When I "worked" on the apple,

some of my energy was
transferred to the apple.

You can think of work, then,
as the transfer of energy.

As I lifted the apple from
the floor to my waist,

the apple gained energy.

You know, guys, energy has many
forms, and we'll get to your list

in just a few minutes, but first
let's focus on two forms of energy:

potential energy and
kinetic energy.

Let's take a look at each.

If I hold the apple still in my
hand, does the apple have energy?

Careful; not all forms of
energy involve movement.

Well, this apple has stored energy.

We call it potential energy.

Holding the apple like this
gives the apple the potential

to fall to the ground.

Now, if I release the
apple, the apple falls.

The potential energy
changes into kinetic energy.

It is pretty obvious when an
object has kinetic energy.

As long as the object is moving,
it's said to have kinetic energy.

What's more difficult to determine
is how much potential energy

an object has.

Let's go back to our
example with the apple.

The potential energy of this apple
really depends on height, how high

or low my hand is from the ground.

We call this type of
potential energy gravitational

potential energy.

Gravitational potential
energy depends on mass,

gravitational acceleration,
and height.

Near the Earth's surface,
gravitational potential energy,

or GPE, is equal to
the product of mass,

gravitational acceleration,
and height.

Remember that "g" is
the acceleration caused

by Earth's gravity, which at
sea level equals 9.8 meters per

second squared.

Let me show you an example.

Suppose a satellite has a mass
of 293 kilograms and we lift it

to the top of Mount Everest.

What is the gravitational
potential energy of the satellite?

Well, what do we know?

We know mass is equal
to 293 kilograms,

gravitational acceleration is equal

to 9.8 meters per second
squared, and we know the height

of Mount Everest, which is
approximately 8,850 meters.

Let's write the equation

for gravitational potential
energy: GPE equals MGH.

Substituting in our values for
mass, acceleration due to gravity,

and height, we get: GPE equals
the product of 293 kilograms,

9.8 meters per second
squared, and 8,850 meters.

The answer turns out to be
approximately 25 million.

Don't forget, I need to
assign a unit to that number.

Units are very important when
explaining scientific concepts.

Do you have any idea what
the unit for energy is?

Let's figure it out.

The original equation
for GPE is MGH.

Mass times gravity
is equal to weight,

and weight is measured in newtons.

Remember, weight is a force.

Therefore, the unit

for gravitational potential
energy is the newton-meter.

Do you remember from earlier

in the program what a
newton-meter is equivalent to?

Well, if you said 1
joule, you're on the ball.

1 newton-meter is
equivalent to 1 joule.

Wait a minute; work is
also measured in joules.

I think we just showed
mathematically how energy

and work are related to each other.

Now let's go back
to kinetic energy.

How much kinetic energy do
you think an object, say,

like a rocket, depends on?

The kinetic energy
of an object depends

on both its mass and its velocity.

The mathematical relationship
between kinetic energy, mass,

and velocity is: KE
equals one-half MV squared.

Notice that the velocity
is squared in the equation.

Remember, guys, the number
2 is called an exponent.

The exponent tells you
how many times a number

or base is used as a factor.

For example: two squared is equal

to two times two,
which equals four.

Three squared is equal
to three times three,

which equals nine, and so on.

The term "V squared" equals
V times V. So are you ready

to try a problem involving
kinetic energy?

Here's one for you.

Norbert's Mars rover, with
a mass of 210 kilograms,

is traveling on the
surface of Mars at a speed

of 6 meters per second.

Zot's rover, with a
mass of 170 kilograms,

is traveling on the surface of
Mars at 8 meters per second.

Predict which rover has
more kinetic energy.

Then, verify your
prediction mathematically.

You may now pause the program.

So did you make the
correct prediction?

Let's double-check your work.

Solving for the kinetic energy
of Norbert's rover, we have:

kinetic energy is equal to
one-half times 219 kilograms,

times six meters per
second, quantity squared.

The kinetic energy of Norbert's
rover is equal to 3,780 joules.

Solving for the kinetic energy
of Zot's rover, we have:

kinetic energy is equal to
one-half times 170 kilograms,

times eight meters per
second, quantity squared.

The kinetic energy of Zot's
rover is equal to 5,440 joules.

So comparing the two values,
we see that the kinetic energy

for Zot's rover is greater

than the kinetic energy
for Norbert's rover.

We now know that an object may
possess both kinetic energy

and potential energy
at the same time.

Let's go back to our
example with the apple.

Any object that rises and
falls...experiences a change

in its kinetic and
potential energy.

Let's look at this
energy transformation

as I toss the apple into the air.

When the apple moves, it
possesses kinetic energy.

As it rises, it slows down.

Its kinetic energy decreases.

Because the height increases,
its potential energy increases.

At the highest point, the
apple actually stops moving.

At this point, it no
longer has kinetic energy,

but it has maximum
potential energy.

As the apple falls, the
kinetic energy increases,

and the potential energy decreases.

No matter how energy is
transformed or transferred,

all of the energy is still present
somewhere in one form or another.

This statement is known as the
law of conservation of energy.

As long as you account for all the
different forms of energy involved

in any process, you will
find that the total amount

of energy never changes.

In other words, energy cannot
be created or destroyed.

It just changes form.

So, do you think you have a pretty
good idea of what work and energy,

specifically potential and
kinetic energy, are all about?

Well, good, because now it's time

to preview this program's
hands-on activity.

The NASA Explorer School students
from Martinsville Middle School

in Martinsville, Virginia,

will preview this
program's hands-on activity.

Hi. NASA Connect asked us
to show you this program's

hands-on activity.

In this activity, students will
do an inquiry investigation

on the relationship between
the height from which a marble

on a ramp is released and the
distance a milk carton at the end

of the ramp is moved
along the floor

after the ball collides
with the carton.

You can download a copy
of the educators' guide

from the NASA Connect website for
directions and a list of materials.

Before you start the activity,
your teacher will ask you to answer

and discuss several
critical-thinking questions based

on the experimental set-up.

Set up the ramp by using tape to
mark one end 0.7 meters high up,

and place an empty milk carton
at the other end of the ramp,

so that it will catch the marble
after it rolls down the ramp.

You will roll a marble from
five different measured heights.

Line up a meter stick on
the floor along the distance

that the milk carton will travel
after being hit by the marble.

Starting at the first
height marked on the ramp,

release the marble down the ramp.

On the data collection
chart under "Trial 1,"

record the linear distance
that the milk carton travels

after the marble hit it.

You will conduct four more trials.

Record the distance the
milk carton travels.

Calculate and record the average
distance the milk carton traveled.

Continue the experiment
by increasing the height

from which you drop the
marble by 0.1 meter each time.

Students will analyze their data
by calculating the potential energy

that the marble has at each
height and the kinetic energy

that the marble has at
the end of each roll.

Now is your chance to put your
algebra skills to the test.

Keep in mind that for this
activity, you will need

to ignore energy lost
because of friction.

Based on the data you collect,

you will graphically show the
relationship between the height

from which the marble is dropped

and the distance the
carton is moved.

From the graph, select
another designated height,

and predict how far the
milk carton will move

if the marble is released.

Go ahead and test your prediction.

Were you correct?

Don't forget to check out the
web activity for this program.

You can download it from
the NASA Connect website.

Now that you have a basic
understanding of energy,

let's hear about some
innovative propulsion technologies

that NASA is developing for
future space exploration.

And don't forget, you
are the future explorers.

Thanks, Jennifer.

Space is big.

Distances to Mars and
beyond are so large

that when using today's
spacecraft technology,

we can only send relatively
small spacecraft.

In other words, distance affects
the mass that we can send.

NASA is working on a new way
of powering space vehicles

that will enable us to send
more complex spacecraft to Mars,

Jupiter, and beyond, and may
even shorten the travel time.

The new program is
called Prometheus.

It will provide a giant
leap in our ability

to explore our solar system.

The program focuses
on using nuclear power

in long-distance spacecraft.

The nuclear power system
will create electricity

that will be used for two things.

One job will be to
propel the spacecraft.

The other will be to provide power
for the instruments on board.

This capability will let NASA
send spacecraft to places

that we currently want to reach.

It would also allow us to
do more scientific work

when the spacecraft
reaches its destination

and could even help speed up
travel through the solar system.

Many space missions
have used nuclear power.

The farthest known man-made object
is the nuclear-powered spacecraft

called Voyager 1.

This probe has been
used for over 26 years.

It is now over 8 billion
miles away.

That's more than twice the
distance from the Sun to Pluto.

Remember earlier in the
program, Jennifer asked you

to list some forms of energy?

On my list, I have mechanical
energy, thermal energy,

chemical energy, electromagnetic
energy, and nuclear energy.

Project Prometheus will
be using nuclear energy

to help power the spacecraft.

Nuclear energy is the energy
stored in the nucleus of an atom.

In a nuclear reaction,
a tiny portion

of an atom's mass is
turned into energy.

Scientists are studying
two different ways

of using the energy stored
within the nucleus of an atom.

The first approach
is to take an atom

that is naturally very unstable,
which means that the atom wants

to change into a different,
more stable atom.

During this change, the atom
releases tiny particles,

causing the material to heat up.

This process is known
as radioactive decay.

The released particles
are called radiation.

The heat that is released
can be harnessed

and converted to electrical energy.

This energy can then be used to
power the spacecraft systems.

It is called radioisotope decay.

The second approach is to break
apart the nucleus of the atom

to release even more energy
than radioactive decay.

This process is called
nuclear fission.

It is used in nuclear power
plants all around the world

to produce electricity.

Nuclear fission systems can
generate large amounts of power.

Think of this comparison.

A radioisotope power system
could create enough power

to light a few light bulbs.

A nuclear fission power system
could create enough energy

to power a laundromat.

This increased amount
of energy means

that a nuclear fission
energy system could do more

than just power a spacecraft's
scientific instruments.

It could also be used to run the
engines that propel the rocket.

NASA hopes to use
this technology soon.

In fact, it's already
working on the first probe

to use this technology.

This probe is the
Prometheus-1 mission.

This mission will use a
nuclear fission system.

This system would provide energy

for both spacecraft
electrical power and propulsion.

Prometheus-1 would orbit three
of the larger moons of Jupiter:

Callisto, Ganymede, and Europa.

Europa is one of our solar system's
most fascinating celestial bodies.

Europa's surface is
completely covered in ice,

but scientists believe that the
solar system's largest oceans could

be hidden under that ice.

If oceans are indeed present,
there is a possibility

that life could be found there.

The Pometheus-1 mission
will be finding answers

to the mysteries of these moons.

One day, the same power
and propulsion systems used

on Prometheus-1 could
be used to send probes

to other far-off places.

These systems will even be
used to support human missions

to explore the solar
system and beyond.

Back to you, Jennifer.

Thanks, Anita.

Sounds pretty cool.

You know, NASA is working on
another propulsion technology.

It's called VASIMR.

Dr. Franklin Chang-Diaz can tell
us more about that technology.

Thank you.

My name is Franklin Chang-Diaz.

I am an astronaut and director

of the Advanced Space
Propulsion Laboratory.

I would like to share with you
another possible advanced space

propulsion technology that we've
been working on for many years.

It is called the Variable Specific
Impulse Magnetoplasma Rocket,

or VASIMR for short.

This new engine would allow
for much faster space travel

than what we can do today.

VASIMR is a plasma-based
propulsion system.

Do you remember the
four states of matter?

They are: solid, liquid,
gas, and plasma.

You can go from one state
to the other by adding

or subtracting heat
from the material.

Take water, for example.

Its solid state is ice.

Add heat, and you get liquid.

Add more heat, and
you get gas or vapor.

If you add even more
heat to the gas,

the atoms in it get torn or broken.

Remember, each atom is sort of like
an egg: it has a central nucleus,

the yoke, with positive
particles in it called protons;

and a blanket, the white,

of negative-charged particles
called electrons in it.

When the atom gets torn,
these charges are free to roam

around every which way.

Scrambled eggs.

Such a mixture of charged
particles is called plasma.

Plasmas are very hot, with
temperatures of hundreds

of thousands to millions
of degrees.

The Sun and the stars
are made of plasma.

Plasmas are very good
conductors of electricity,

and they respond very well to
electric and magnetic fields.

We use these properties to heat
them and also to confine them

and use their extreme heat to
produce awesome rocket propulsion.

Electric fields heat the
plasma and speed it up.

Magnetic fields direct the
plasma in the right direction

as it is pushed out of the engine.

This creates thrust
for the spacecraft.

Possible fuels for the VASIMR
engine could include hydrogen,

deuterium, helium,
nitrogen, and others.

The use of hydrogen as a fuel

for the project would
also have other benefits.

Hydrogen can be found
all throughout space.

This means we are likely
to find plentiful supplies

of fuel everywhere we go, and
we could refuel the spacecraft

for the return trip to Earth.

Also, strong magnetic fields
and liquid hydrogen make

for great radiation shields.

This means the hydrogen
fuel for the VASIMR engine,

as well as the magnet technology
we are developing for it,

could both also be used to
protect the astronaut crew

from dangerous radiation
exposure during the flight.

This is how technology developed
for one thing can also be used

for another equally
important purpose.

To heat and accelerate the
plasma in deep-space flights,

VASIMR will use electricity
from nuclear power.

VASIMR is still years away
from transporting humans

and cargo to Mars and beyond.

Remember the scenario
that Jennifer gave you

at the beginning of the program.

Our team can only take this
advanced technology so far.

And then it will be up to you.

Your generation will make this
space propulsion system a reality.

Some of you may one day fly on
it and become the astronauts

that will build the
first base on Mars.

I've been in space seven times,
but you will be the astronauts

who will get a chance to explore
the moon, Mars, and beyond.

You are the next generation
of explorers.

So, good luck.

Back to you, Jennifer.

My thanks, Dr. Chang-Diaz.

You know, I can't wait for the day

when we receive the first
transmission from people on Mars,

and maybe you'll be one of them.

Well, that wraps up another
episode of NASA Connect.

We'd like to thank everyone who
helped make this program possible.

Got a comment, question,
or suggestion?

Well, email them to
"connect at"

And don't forget to check out
this program's student challenge.

You can find it on the
NASA Connect website.

So until next time,
stay connected to math,

science, technology, and NASA.

And maybe we'll see you on Mars.


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