This material was developed for the Live From Mars project
by Passport to Knowledge. Live
From Mars was a precursor to Mars Team Online.
Activity 1.1.A: Rocket Science
Without the mighty Saturn V rockets, there could have been no Apollo program
and no humans on the Moon. Without the smaller, cheaper Delta II 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 principles of physics.
Simple balloon rockets, for example, offer great opportunities for students
to explore the Laws of Motion. These laws were first expressed by the
English scientist, Sir Isaac Newton (1642-1727).
| 1. Newton's First Law:
Objects at rest will stay at rest and objects in motion
will move in a straight line at constant speed 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.)
| 2. 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.)
| 3. 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)
| 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
object's 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 to the action, or
thrust, from the engine (Third Law).
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 does not move. When the nozzle
is released, air escapes through it in one direction and the
balloon is propelled in the opposite direction.
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 or 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
Mars Mission Logbooks
Materials for whole class
Large printed signs of Newton's Laws of Motion
Show students a video of a rocket or Space Shuttle being launched
and continuing up into orbit. (Most NASA Mission films will show this.)
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.
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. 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 Science 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
3. Discuss the results of the balloon rocket experiments with
the students. In particular, ask the following:
Research (using print or on-line sources) the Delta II 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?