Live From Mars was active July 1996-December 1997.
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
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
(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
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
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 or chalkboard.
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?