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Transcript for NASA Connect - Rocket to The Stars
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Hey, hey, hey!
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I'm Kenan Thompson.
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But I play Fat Albert in
the live-action film based
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on Bill Cosby's hit show.
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On this episode of NASA Connect,
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you'll learn about the science
concepts of work and energy.
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You will also see how
we can use algebra
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to help explain both concepts.
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NASA engineers and scientists
will introduce you to exciting
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and innovative space propulsion
technologies of the future.
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And in your classroom, you'll
apply your math and science skills
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by conducting a really
cool hands-on activity.
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So stay tuned as host
Jennifer Pulley takes you
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on another exciting
episode of NASA Connect:
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"Rocket to the Stars."
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Hi, I'm Jennifer Pulley,
and welcome to NASA Connect,
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the show that connects you to math,
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science, technology, and NASA.
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Imagine it's the year 2040.
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You and a team of
international scientists are part
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of the exploration crew
that will begin construction
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of the first human base on Mars.
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You are laying the groundwork for
the next generation of explorers
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to explore Mars and beyond.
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It's not an easy task, but
you are up to the challenge.
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All your years of
schooling, training,
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and hard work have
finally paid off.
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Does it sound like
a fantasy to you?
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Actually, it's not.
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NASA is ready to make the next step
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to exploring the solar
system and beyond.
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And they need your help.
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NASA is looking for bright
young engineers, scientists,
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and researchers who
will make the new vision
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for space exploration a reality.
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For you, it starts right
now, in the classroom.
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Now, during the course of this
program, you will be asked
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to answer several
inquiry-based questions.
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After the questions
appear on the screen,
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your teacher will pause the
program to allow you time to answer
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and discuss the questions.
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This is your time to explore
and become critical thinkers.
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Students, working in
groups, take a few minutes
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to answer the following the
questions: One, what comes to mind
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when you think of work?
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Two, how are work
and energy related?
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Three, what are some
forms of energy?
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Briefly describe them and
give examples of each.
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It is now time to pause the
program and answer the questions.
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So, guys, how did you
do with the questions?
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Great job.
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Okay, let's get started.
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So what is work?
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Well, most people would say they
are working when they do anything
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that requires a physical...or
a mental effort.
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Now, in scientific terms,
work is the use of force
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to move an object
a certain distance.
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More specifically, to
do work on an object,
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some part of the force you exert
must be in the same direction
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as the object's motion.
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Let's look at the
following two examples.
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On the left side,
Norbert is lifting a stack
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of textbooks from the floor.
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And on the right side, he is
carrying the stack of textbooks.
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Note the direction of the applied
force and motion for each example.
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In which example is
Norbert actually doing work?
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If you said the left
side, you are correct.
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Why isn't Norbert doing work
in the example on the right?
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Well, because no part
of the applied force is
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in the same direction
as the object's motion.
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When the force is in the
same direction as the motion,
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we can determine the amount of
work being done on an object
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by multiplying force
times distance.
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What are the units for work?
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You know that force
is measured in newtons
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and distance can be
measured in meters.
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The product of a force measured in
newtons and the distance measured
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in meters is a measurement called
a newton-meter, or the joule.
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The joule is the standard
unit used to measure work.
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1 joule of work is
done when a force
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of 1 newton moves
an object 1 meter.
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Do you have any idea how
much a joule of work is?
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I know. Let's take an apple,
which weighs about 1 newton.
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Now, if you lift the apple
from the floor to your waist,
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which is about 1 meter, you do
1 joule of work on the apple.
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But what happens if I
want to lift 100 apples?
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For me, that would
take a lot of force,
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and I don't think I have
enough energy to do that.
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Let's go back to our
example with the apple.
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Now, I easily have enough energy
to lift this apple from the floor
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to my waist, and I know I'm doing
work on the apple as I lift it.
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So there must be a relationship
between work and energy, right?
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When I lifted the apple from
the floor, I caused a change.
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In this case, the change is
in the position of the apple.
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An object that has energy has
the ability to cause change
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or the ability to do work.
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When I "worked" on the apple,
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some of my energy was
transferred to the apple.
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You can think of work, then,
as the transfer of energy.
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As I lifted the apple from
the floor to my waist,
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the apple gained energy.
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You know, guys, energy has many
forms, and we'll get to your list
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in just a few minutes, but first
let's focus on two forms of energy:
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potential energy and
kinetic energy.
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Let's take a look at each.
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If I hold the apple still in my
hand, does the apple have energy?
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Careful; not all forms of
energy involve movement.
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Well, this apple has stored energy.
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We call it potential energy.
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Holding the apple like this
gives the apple the potential
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to fall to the ground.
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Now, if I release the
apple, the apple falls.
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The potential energy
changes into kinetic energy.
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It is pretty obvious when an
object has kinetic energy.
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As long as the object is moving,
it's said to have kinetic energy.
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What's more difficult to determine
is how much potential energy
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an object has.
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Let's go back to our
example with the apple.
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The potential energy of this apple
really depends on height, how high
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or low my hand is from the ground.
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We call this type of
potential energy gravitational
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potential energy.
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Gravitational potential
energy depends on mass,
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gravitational acceleration,
and height.
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Near the Earth's surface,
gravitational potential energy,
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or GPE, is equal to
the product of mass,
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gravitational acceleration,
and height.
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Remember that "g" is
the acceleration caused
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by Earth's gravity, which at
sea level equals 9.8 meters per
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second squared.
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Let me show you an example.
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Suppose a satellite has a mass
of 293 kilograms and we lift it
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to the top of Mount Everest.
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What is the gravitational
potential energy of the satellite?
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Well, what do we know?
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We know mass is equal
to 293 kilograms,
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gravitational acceleration is equal
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to 9.8 meters per second
squared, and we know the height
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of Mount Everest, which is
approximately 8,850 meters.
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Let's write the equation
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for gravitational potential
energy: GPE equals MGH.
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Substituting in our values for
mass, acceleration due to gravity,
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and height, we get: GPE equals
the product of 293 kilograms,
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9.8 meters per second
squared, and 8,850 meters.
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The answer turns out to be
approximately 25 million.
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Don't forget, I need to
assign a unit to that number.
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Units are very important when
explaining scientific concepts.
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Do you have any idea what
the unit for energy is?
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Let's figure it out.
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The original equation
for GPE is MGH.
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Mass times gravity
is equal to weight,
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and weight is measured in newtons.
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Remember, weight is a force.
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Therefore, the unit
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for gravitational potential
energy is the newton-meter.
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Do you remember from earlier
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in the program what a
newton-meter is equivalent to?
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Well, if you said 1
joule, you're on the ball.
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1 newton-meter is
equivalent to 1 joule.
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Wait a minute; work is
also measured in joules.
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I think we just showed
mathematically how energy
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and work are related to each other.
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Now let's go back
to kinetic energy.
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How much kinetic energy do
you think an object, say,
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like a rocket, depends on?
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The kinetic energy
of an object depends
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on both its mass and its velocity.
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The mathematical relationship
between kinetic energy, mass,
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and velocity is: KE
equals one-half MV squared.
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Notice that the velocity
is squared in the equation.
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Remember, guys, the number
2 is called an exponent.
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The exponent tells you
how many times a number
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or base is used as a factor.
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For example: two squared is equal
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to two times two,
which equals four.
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Three squared is equal
to three times three,
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which equals nine, and so on.
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The term "V squared" equals
V times V. So are you ready
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to try a problem involving
kinetic energy?
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Here's one for you.
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Norbert's Mars rover, with
a mass of 210 kilograms,
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is traveling on the
surface of Mars at a speed
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of 6 meters per second.
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Zot's rover, with a
mass of 170 kilograms,
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is traveling on the surface of
Mars at 8 meters per second.
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Predict which rover has
more kinetic energy.
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Then, verify your
prediction mathematically.
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You may now pause the program.
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So did you make the
correct prediction?
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Let's double-check your work.
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Solving for the kinetic energy
of Norbert's rover, we have:
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kinetic energy is equal to
one-half times 219 kilograms,
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times six meters per
second, quantity squared.
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The kinetic energy of Norbert's
rover is equal to 3,780 joules.
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Solving for the kinetic energy
of Zot's rover, we have:
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kinetic energy is equal to
one-half times 170 kilograms,
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times eight meters per
second, quantity squared.
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The kinetic energy of Zot's
rover is equal to 5,440 joules.
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So comparing the two values,
we see that the kinetic energy
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for Zot's rover is greater
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than the kinetic energy
for Norbert's rover.
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We now know that an object may
possess both kinetic energy
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and potential energy
at the same time.
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Let's go back to our
example with the apple.
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Any object that rises and
falls...experiences a change
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in its kinetic and
potential energy.
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Let's look at this
energy transformation
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as I toss the apple into the air.
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When the apple moves, it
possesses kinetic energy.
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As it rises, it slows down.
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Its kinetic energy decreases.
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Because the height increases,
its potential energy increases.
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At the highest point, the
apple actually stops moving.
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At this point, it no
longer has kinetic energy,
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but it has maximum
potential energy.
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As the apple falls, the
kinetic energy increases,
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and the potential energy decreases.
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No matter how energy is
transformed or transferred,
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all of the energy is still present
somewhere in one form or another.
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This statement is known as the
law of conservation of energy.
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As long as you account for all the
different forms of energy involved
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in any process, you will
find that the total amount
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of energy never changes.
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In other words, energy cannot
be created or destroyed.
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It just changes form.
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So, do you think you have a pretty
good idea of what work and energy,
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specifically potential and
kinetic energy, are all about?
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Well, good, because now it's time
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to preview this program's
hands-on activity.
[00:14:56.070]
[00:14:57.810]
The NASA Explorer School students
from Martinsville Middle School
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in Martinsville, Virginia,
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will preview this
program's hands-on activity.
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Hi. NASA Connect asked us
to show you this program's
[00:15:11.280]
hands-on activity.
[00:15:12.580]
In this activity, students will
do an inquiry investigation
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on the relationship between
the height from which a marble
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on a ramp is released and the
distance a milk carton at the end
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of the ramp is moved
along the floor
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after the ball collides
with the carton.
[00:15:27.860]
You can download a copy
of the educators' guide
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from the NASA Connect website for
directions and a list of materials.
[00:15:34.120]
Before you start the activity,
your teacher will ask you to answer
[00:15:38.210]
and discuss several
critical-thinking questions based
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on the experimental set-up.
[00:15:45.190]
Set up the ramp by using tape to
mark one end 0.7 meters high up,
[00:15:50.810]
and place an empty milk carton
at the other end of the ramp,
[00:15:54.150]
so that it will catch the marble
after it rolls down the ramp.
[00:15:58.290]
You will roll a marble from
five different measured heights.
[00:16:02.310]
Line up a meter stick on
the floor along the distance
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that the milk carton will travel
after being hit by the marble.
[00:16:09.170]
Starting at the first
height marked on the ramp,
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release the marble down the ramp.
[00:16:16.560]
On the data collection
chart under "Trial 1,"
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record the linear distance
that the milk carton travels
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after the marble hit it.
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You will conduct four more trials.
[00:16:29.670]
Record the distance the
milk carton travels.
[00:16:32.900]
Calculate and record the average
distance the milk carton traveled.
[00:16:39.100]
Continue the experiment
by increasing the height
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from which you drop the
marble by 0.1 meter each time.
[00:16:46.810]
Students will analyze their data
by calculating the potential energy
[00:16:51.830]
that the marble has at each
height and the kinetic energy
[00:16:55.880]
that the marble has at
the end of each roll.
[00:16:58.900]
Now is your chance to put your
algebra skills to the test.
[00:17:03.200]
Keep in mind that for this
activity, you will need
[00:17:06.550]
to ignore energy lost
because of friction.
[00:17:11.010]
Based on the data you collect,
[00:17:12.890]
you will graphically show the
relationship between the height
[00:17:17.190]
from which the marble is dropped
[00:17:19.150]
and the distance the
carton is moved.
[00:17:22.940]
From the graph, select
another designated height,
[00:17:25.770]
and predict how far the
milk carton will move
[00:17:28.760]
if the marble is released.
[00:17:30.630]
Go ahead and test your prediction.
[00:17:33.430]
Were you correct?
[00:17:35.590]
Don't forget to check out the
web activity for this program.
[00:17:38.830]
You can download it from
the NASA Connect website.
[00:17:41.500]
Now that you have a basic
understanding of energy,
[00:17:47.000]
let's hear about some
innovative propulsion technologies
[00:17:50.180]
that NASA is developing for
future space exploration.
[00:17:53.850]
And don't forget, you
are the future explorers.
[00:17:57.610]
Thanks, Jennifer.
[00:17:58.740]
Space is big.
[00:18:00.320]
Distances to Mars and
beyond are so large
[00:18:03.440]
that when using today's
spacecraft technology,
[00:18:06.030]
we can only send relatively
small spacecraft.
[00:18:09.380]
In other words, distance affects
the mass that we can send.
[00:18:13.430]
NASA is working on a new way
of powering space vehicles
[00:18:17.740]
that will enable us to send
more complex spacecraft to Mars,
[00:18:22.130]
Jupiter, and beyond, and may
even shorten the travel time.
[00:18:26.220]
The new program is
called Prometheus.
[00:18:28.930]
It will provide a giant
leap in our ability
[00:18:31.580]
to explore our solar system.
[00:18:33.670]
The program focuses
on using nuclear power
[00:18:37.090]
in long-distance spacecraft.
[00:18:39.540]
The nuclear power system
will create electricity
[00:18:42.210]
that will be used for two things.
[00:18:44.410]
One job will be to
propel the spacecraft.
[00:18:47.370]
The other will be to provide power
for the instruments on board.
[00:18:51.200]
This capability will let NASA
send spacecraft to places
[00:18:54.680]
that we currently want to reach.
[00:18:56.860]
It would also allow us to
do more scientific work
[00:19:00.310]
when the spacecraft
reaches its destination
[00:19:02.690]
and could even help speed up
travel through the solar system.
[00:19:06.900]
Many space missions
have used nuclear power.
[00:19:09.900]
The farthest known man-made object
is the nuclear-powered spacecraft
[00:19:13.860]
called Voyager 1.
[00:19:15.620]
This probe has been
used for over 26 years.
[00:19:19.360]
It is now over 8 billion
miles away.
[00:19:22.370]
That's more than twice the
distance from the Sun to Pluto.
[00:19:26.070]
Remember earlier in the
program, Jennifer asked you
[00:19:28.700]
to list some forms of energy?
[00:19:30.690]
On my list, I have mechanical
energy, thermal energy,
[00:19:35.110]
chemical energy, electromagnetic
energy, and nuclear energy.
[00:19:39.730]
Project Prometheus will
be using nuclear energy
[00:19:42.450]
to help power the spacecraft.
[00:19:44.720]
Nuclear energy is the energy
stored in the nucleus of an atom.
[00:19:48.470]
In a nuclear reaction,
a tiny portion
[00:19:51.180]
of an atom's mass is
turned into energy.
[00:19:53.880]
Scientists are studying
two different ways
[00:19:56.480]
of using the energy stored
within the nucleus of an atom.
[00:20:00.360]
The first approach
is to take an atom
[00:20:02.440]
that is naturally very unstable,
which means that the atom wants
[00:20:06.350]
to change into a different,
more stable atom.
[00:20:09.730]
During this change, the atom
releases tiny particles,
[00:20:13.490]
causing the material to heat up.
[00:20:15.780]
This process is known
as radioactive decay.
[00:20:18.840]
The released particles
are called radiation.
[00:20:21.620]
The heat that is released
can be harnessed
[00:20:24.410]
and converted to electrical energy.
[00:20:26.980]
This energy can then be used to
power the spacecraft systems.
[00:20:30.850]
It is called radioisotope decay.
[00:20:33.840]
The second approach is to break
apart the nucleus of the atom
[00:20:37.620]
to release even more energy
than radioactive decay.
[00:20:41.090]
This process is called
nuclear fission.
[00:20:43.970]
It is used in nuclear power
plants all around the world
[00:20:47.180]
to produce electricity.
[00:20:48.940]
Nuclear fission systems can
generate large amounts of power.
[00:20:53.100]
Think of this comparison.
[00:20:54.870]
A radioisotope power system
could create enough power
[00:20:58.280]
to light a few light bulbs.
[00:21:00.350]
A nuclear fission power system
could create enough energy
[00:21:04.000]
to power a laundromat.
[00:21:05.830]
This increased amount
of energy means
[00:21:07.810]
that a nuclear fission
energy system could do more
[00:21:11.280]
than just power a spacecraft's
scientific instruments.
[00:21:14.730]
It could also be used to run the
engines that propel the rocket.
[00:21:18.900]
NASA hopes to use
this technology soon.
[00:21:21.530]
In fact, it's already
working on the first probe
[00:21:24.030]
to use this technology.
[00:21:25.330]
This probe is the
Prometheus-1 mission.
[00:21:28.440]
This mission will use a
nuclear fission system.
[00:21:30.960]
This system would provide energy
[00:21:33.910]
for both spacecraft
electrical power and propulsion.
[00:21:37.800]
Prometheus-1 would orbit three
of the larger moons of Jupiter:
[00:21:42.150]
Callisto, Ganymede, and Europa.
[00:21:45.100]
Europa is one of our solar system's
most fascinating celestial bodies.
[00:21:49.840]
Europa's surface is
completely covered in ice,
[00:21:52.730]
but scientists believe that the
solar system's largest oceans could
[00:21:56.920]
be hidden under that ice.
[00:21:58.920]
If oceans are indeed present,
there is a possibility
[00:22:02.120]
that life could be found there.
[00:22:04.540]
The Pometheus-1 mission
will be finding answers
[00:22:07.310]
to the mysteries of these moons.
[00:22:09.560]
One day, the same power
and propulsion systems used
[00:22:12.550]
on Prometheus-1 could
be used to send probes
[00:22:15.650]
to other far-off places.
[00:22:18.040]
These systems will even be
used to support human missions
[00:22:21.030]
to explore the solar
system and beyond.
[00:22:23.610]
Back to you, Jennifer.
[00:22:25.810]
[00:22:27.450]
Thanks, Anita.
[00:22:28.620]
Sounds pretty cool.
[00:22:31.020]
You know, NASA is working on
another propulsion technology.
[00:22:34.940]
It's called VASIMR.
[00:22:36.770]
Dr. Franklin Chang-Diaz can tell
us more about that technology.
[00:22:40.790]
Thank you.
[00:22:44.290]
My name is Franklin Chang-Diaz.
[00:22:46.490]
I am an astronaut and director
[00:22:48.400]
of the Advanced Space
Propulsion Laboratory.
[00:22:50.880]
I would like to share with you
another possible advanced space
[00:22:54.470]
propulsion technology that we've
been working on for many years.
[00:22:58.240]
It is called the Variable Specific
Impulse Magnetoplasma Rocket,
[00:23:03.110]
or VASIMR for short.
[00:23:04.690]
This new engine would allow
for much faster space travel
[00:23:08.180]
than what we can do today.
[00:23:10.040]
VASIMR is a plasma-based
propulsion system.
[00:23:14.250]
Do you remember the
four states of matter?
[00:23:17.150]
They are: solid, liquid,
gas, and plasma.
[00:23:23.000]
You can go from one state
to the other by adding
[00:23:26.750]
or subtracting heat
from the material.
[00:23:29.690]
Take water, for example.
[00:23:31.340]
Its solid state is ice.
[00:23:33.790]
Add heat, and you get liquid.
[00:23:36.200]
Add more heat, and
you get gas or vapor.
[00:23:39.290]
If you add even more
heat to the gas,
[00:23:42.900]
the atoms in it get torn or broken.
[00:23:46.050]
Remember, each atom is sort of like
an egg: it has a central nucleus,
[00:23:51.590]
the yoke, with positive
particles in it called protons;
[00:23:56.390]
and a blanket, the white,
[00:23:58.840]
of negative-charged particles
called electrons in it.
[00:24:03.500]
When the atom gets torn,
these charges are free to roam
[00:24:07.760]
around every which way.
[00:24:10.700]
Scrambled eggs.
[00:24:12.980]
Such a mixture of charged
particles is called plasma.
[00:24:18.110]
Plasmas are very hot, with
temperatures of hundreds
[00:24:21.760]
of thousands to millions
of degrees.
[00:24:25.100]
The Sun and the stars
are made of plasma.
[00:24:28.970]
Plasmas are very good
conductors of electricity,
[00:24:32.080]
and they respond very well to
electric and magnetic fields.
[00:24:37.180]
We use these properties to heat
them and also to confine them
[00:24:42.650]
and use their extreme heat to
produce awesome rocket propulsion.
[00:24:48.250]
Electric fields heat the
plasma and speed it up.
[00:24:52.400]
Magnetic fields direct the
plasma in the right direction
[00:24:56.520]
as it is pushed out of the engine.
[00:24:58.900]
This creates thrust
for the spacecraft.
[00:25:02.130]
Possible fuels for the VASIMR
engine could include hydrogen,
[00:25:07.470]
deuterium, helium,
nitrogen, and others.
[00:25:12.250]
The use of hydrogen as a fuel
[00:25:15.190]
for the project would
also have other benefits.
[00:25:19.080]
Hydrogen can be found
all throughout space.
[00:25:22.940]
This means we are likely
to find plentiful supplies
[00:25:26.470]
of fuel everywhere we go, and
we could refuel the spacecraft
[00:25:31.770]
for the return trip to Earth.
[00:25:34.130]
Also, strong magnetic fields
and liquid hydrogen make
[00:25:38.740]
for great radiation shields.
[00:25:41.360]
This means the hydrogen
fuel for the VASIMR engine,
[00:25:45.140]
as well as the magnet technology
we are developing for it,
[00:25:50.000]
could both also be used to
protect the astronaut crew
[00:25:55.070]
from dangerous radiation
exposure during the flight.
[00:25:58.810]
This is how technology developed
for one thing can also be used
[00:26:04.100]
for another equally
important purpose.
[00:26:07.220]
To heat and accelerate the
plasma in deep-space flights,
[00:26:12.340]
VASIMR will use electricity
from nuclear power.
[00:26:17.040]
VASIMR is still years away
from transporting humans
[00:26:22.270]
and cargo to Mars and beyond.
[00:26:25.420]
Remember the scenario
that Jennifer gave you
[00:26:28.250]
at the beginning of the program.
[00:26:30.290]
Our team can only take this
advanced technology so far.
[00:26:35.280]
And then it will be up to you.
[00:26:37.400]
Your generation will make this
space propulsion system a reality.
[00:26:43.320]
Some of you may one day fly on
it and become the astronauts
[00:26:47.700]
that will build the
first base on Mars.
[00:26:51.050]
I've been in space seven times,
but you will be the astronauts
[00:26:55.840]
who will get a chance to explore
the moon, Mars, and beyond.
[00:27:00.930]
You are the next generation
of explorers.
[00:27:03.870]
So, good luck.
[00:27:06.290]
Back to you, Jennifer.
[00:27:08.220]
[00:27:09.850]
My thanks, Dr. Chang-Diaz.
[00:27:12.040]
You know, I can't wait for the day
[00:27:14.020]
when we receive the first
transmission from people on Mars,
[00:27:18.340]
and maybe you'll be one of them.
[00:27:20.450]
Well, that wraps up another
episode of NASA Connect.
[00:27:24.280]
We'd like to thank everyone who
helped make this program possible.
[00:27:27.840]
Got a comment, question,
or suggestion?
[00:27:30.570]
Well, email them to
"connect at larc.nasa.gov."
[00:27:36.200]
And don't forget to check out
this program's student challenge.
[00:27:40.410]
You can find it on the
NASA Connect website.
[00:27:43.350]
So until next time,
stay connected to math,
[00:27:46.530]
science, technology, and NASA.
[00:27:49.850]
And maybe we'll see you on Mars.
[00:27:52.130]