# Live From Mars Teacher's Guide Preview: Activity 1.1

From: jwee@mail.arc.nasa.gov (Jan Wee)
Subject: Live From Mars Teacher's Guide Preview: Activity 1.1
Date: Fri, 04 Oct 1996 15:22:57 -0500

```Dear discuss-lfm members,

For your preview... Activity 1.1 from the Live From Mars
Teacher's Guide.  Remember, these files are *not*
in final copy form but for your convenience to assist
you as you prepare for the Live from Mars project. The
final print version of the Teacher's Guide will be
shipping by the end of next week!

Jan Wee

-------------------------------------------------------

Activity 1.1.A: Rocket Science 101

Teacher Background
Without the mighty Saturn V rockets, there could have been no
Apollo program and no humans on the Moon. Without the smaller,
cheaper Delta 2 rockets, MGS and MPF would not have been
affordable. Weight, cost, thrust, power... all these are critical to the
exploration of our Cosmos. This set of Activities will expose your
students to some fundamentals of rocket science, and some key
physics principles .

Simple balloon rockets, for example, offer great opportunities for
students to explore the Laws of Motion. These laws were first
expressed by the English physicist, Sir Isaac Newton (1642-1727).

Newton's First Law: Objects at rest will stay at rest and objects in
motion will stay in motion in a straight line unless acted upon by an
unbalanced force.

(i.e., If something is at rest (not moving), it will stay at rest unless
something pushes or pulls on it -- that is, exerts a force on it. Also,
if something is moving in a straight line at a constant speed, it will
continue to move that way unless something pushes or pulls on it.)

Newton's Second Law: Force is equal to mass times acceleration.

f=ma

(i.e., If you push or pull on something, that force can change the
object's speed and/or direction. The greater the force, the greater
can be the resulting change in the object's speed and/or direction.
But, for a given force, you will have less effect on a massive object
than a less massive one.)

Newton's Third Law: For every action there is always an opposite and
equal reaction.

(which translates as: if you push on something, it will "push back"
with an equal amount of force)

In its simplest form, a rocket is a chamber enclosing gas under
pressure. A small opening at one end of the chamber allows the gas
to escape, and by so doing provides a thrust which propels the rocket
in the opposite direction. There's a strong similarity between the
mightiest rocket and a humble balloon. The air inside a fastened
balloon is compressed by the rubber walls. The air pushes back so
that inward and outward forces balance: the balloon is static. When
the nozzle is released, air escapes through it and the balloon is
propelled in the opposite direction.

Newton's Laws in rocket motion
To summarize, an unbalanced force must be exerted for a rocket to
lift off from a launch pad or for a spacecraft to change speed or
direction (First Law). The amount of thrust (force) produced by a
rocket engine will be determined by the rate at which the mass of
the rocket fuel burns and the speed of the gas escaping from the
rocket (Second Law) OR if you push or pull on something, that force
can change the objects speed and/or direction. The harder you push
or pull, the greater the effect! The reaction, or motion, of the rocket
is equal to and in the opposite direction of the action, or thrust,
from the engine (Third Law).

Activity 1.1.A Balloon Rockets (or bursting misconceptions)

Objectives
Students will explore aspects of Newton's First and Third Laws of
Motion.
Students will be able to describe the launch and cruise phases of the
MGS and MPF missions in terms of Newton's First and Third Laws of
Motion.
Students will conduct controlled rocketry experiments and analyze
the MGS and MPF missions in terms of the principles of rocketry.

Materials (for each team of 3/4 students)
several balloons which, when fully inflated, are 3 to 5 inches in
diameter and 1-2 feet long (party time!)
several plastic drinking straws (milk shake size)
strong adhesive tape
nylon fishing line
stopwatch or timer
metric measuring tape or meter sticks
Activity 1.1.A Student Worksheet (one for each student)
Mars Mission Logbooks

For whole class
Large printed signs of Newton's Laws of Motion

Vocabulary
acceleration
action/reaction
balanced
force
friction
launch
orbit
payload
rocket

Engage
Show students a video of a rocket or Space Shuttle being launched
and continuing up into orbit (Most NASA mission films will show
this) i.e., a sequence of the last stages of a Shuttle/Mir docking
maneuver. Have students note any changes they observe in the
rocket's speed and direction. Allow time for discussion and students'
sharing of personal experiences with rockets and/or launches.

Explore
Procedure
1. Explain to students that they are going to become flight
engineers for NASA, working in small "Rocket Science Teams", and
that their mission is to investigate how rockets work. This will
involve some fun experiments with rockets made from balloons and,
in the process, testing Newton's famous Laws of Motion. (Along with
Einstein's e=Mc2, these are some of science's "Greatest Hits" or
"Holy of Holies" and we hope these hands-on Activities will give the
sacred text concrete significance.) Place Newton's Laws of Motion
on chalkboard. This Activity will illustrate two of these laws.
2. Demonstrate experimental procedure as outlined on Student
Worksheet 1.1.A. Hand out materials, and answer student questions.
Then allow Rocket Teams time to construct their rockets and
complete the experiment, recording data on individual worksheets as
well as collecting all the teams results on a class data sheet or
chalkboard.
3. Discuss the results of the balloon rocket experiments with the
students. In particular, ask the following:
Did all teams obtain the same data? How can we explain the
differences?
When did the balloon rockets go the farthest? What caused this? (A
greater unbalanced force was applied for a longer period of time.)
How could they test their ideas?
Why did the balloon rockets stop?
(There was a counter-acting force called friction between the string
and the straw.)
If there was no friction between the straw and the nylon string, and
no wall in the way, how would the balloon rockets behave?
(They would keep accelerating until all the fuel was gone because
there would continue to be an unbalanced force on the balloon.)
If there was no friction between the straw and nylon string, no wall
in the way, and no air resistance acting against the deflated shell of
the balloon, how would the rockets behave after they ran out of
fuel?
(They would keep going at the final speed they had when the fuel ran
out.)
Which Law(s) of Motion does this activity illustrate and why?

Expand/Adapt/Connect
Research (using print or online sources) the Delta 2 rockets chosen
by NASA for Mars Global Surveyor and Mars Pathfinder. When were
these rockets designed and built? Have they been used on other space
missions? What are their strengths and limitations?
(check out:
http://mpf.www.jpl.nasa.gov/mpf/delta.html)

Activity 1.1.B: Rockets and Payloads

Objective
Students will investigate and predict the effect of payload on the
amount of energy needed to lift a rocket vertically (thereby working
with Newton's Second Law of Motion).

Materials (for each Rocket Science team of 3/4 students)
2-3 large, long balloons
balloon pump (available in party stores)
fishing line
paper clips (or pennies)
1 dixie cup
straws (milk shake size)
tape
clothes pins
metric scale
Activity 1.1.B Student Worksheet (one for each student)
Mars Mission Logbooks

Engage
Have Rocket Science Teams brainstorm what equipment they would
place on MGS or MPF spacecraft. Would there be any limitations to
the "payload"? (Hopefully, students will suggest that payload weight
was a serious constraint to the equipment that could be carried by
MGS and MPF to Mars.)

Explore
Procedure
1. Place large sign with Newton's Second Law of Motion on
chalkboard and review the formula (force = mass times
acceleration). Have students express this in more colloquial terms,
until you are sure all understand the principle involved. Ask: Using
the same amount of pushing force, which object could you get to
accelerate faster, a Mack truck or a toy wagon? Why? (If F is equal
and you have bigger M, you have to have a smaller A to keep the
equation balanced.)
2. Distribute materials and Student Worksheets. Review
procedure with students and answer any questions.
3. Allow Rocket Science Teams sufficient time to complete
investigation and record data.
4. Call all the groups together and have them post the results of
each of their trials on a data table on the chalkboard. Draw group
conclusions.

Note: In this experiment students first witness action-reaction.
Then they vary the amount of M between the first phase and second
phases of the experiments, and should see a corresponding increase
in the amount of force required. Acceleration is a variable not
addressed , but this should be discussed, along with the effects of
not holding the string vertically which adds drag from friction,
lowers acceleration and changes results, etc.
5. Have teams share the design principles which made their
launches successful and then develop and contribute ideas they think
could be used to create an even more successful "heavy-lift"
launcher.

Expand/Adapt/Connect
Design an experiment to investigate the following:
Can you eliminate the paper cup from the rocket and have it still
carry paper clips?
If each balloon costs one million dollars and you need to lift 100
paper clips, how much money would you need to spend? Can you think
of a way to cut this cost?
Without attaching the paper cup as a payload carrier, measure the
distance the balloon travels along the string in a horizontal,
vertical, and 45 degree angle. Compare and discuss the results.

Go online and find information giving the specific course that MPF
and/or MGS will follow to travel to Mars. How many trajectory
changes will be necessary? How is the spacecraft controlled?

Go online, read Field Journals and bios to find out what course you
need to follow to become a rocket scientist.

Explain (in writing or with illustrations) a spacecraft launch, from
blast-off through entry into orbit, in terms of Newton's Laws of
Motion. Make sure your explanation could be understood by a younger
brother or sister!

Math: Graph data from the rocket experiments.

Language Arts: Write a first-person account of a rocket launch as if
you were Sir Isaac Newton.

Reading:  Read a biography of one of the following scientists
associated with rocketry: Robert Goddard, Johann Schmidlap, Isaac
Newton, Wan Hu, William Congreve, William Hale, Konstantin
Tsiolkovsky, Hermann Oberth.  Report this person's contributions to
science to your class.

Social Studies:
Research Robert Goddard (his boyhood hometown, Worcester,
Massachusetts, will be an uplink site for the first broadcast on
November 19, 1996).

Research why launches are held at Cape Canaveral, Florida.

Research the development of rockets from the earliest to the most
current of NASA designs.  Then add your own design! Present your
report using computer presentation software (HyperCard,
HyperStudio, etc.)

Art:  Design your own rocket and translate into two-dimensional
drawing or three-dimensional model.

Suggested URLs
http://www.jpl.nasa.gov/basics
http://www.nar.org

```