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Grade:
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Science
Grade: Middle
Subject: Science

#887. Using Newton's Laws with 2 Liter Bottle Rockets

Science, level: Middle
Posted Wed Mar 10 09:21:19 PST 1999 by Joel Moore (JMOORE4@prodigy.net).

Union Elementary, Warsaw, OH
Materials Required: 2 Liter bottles, cardboard, tape, launching mechanism
Activity Time: 6-8 class periods
Concepts Taught: History, Physics, Graphs, Formulas

ROCKETS
We do this lesson in the spring of the year as part of our sixth grade space unit. It involves a brief history of
rockets and continues with Newton's Laws of Motion. We culminate the mini unit by building and
launching 2 liter bottle rockets where we use formulas and charts to measure height and velocity.
The reference source for the notes and the assembly of the bottle rockets are from The Ohio State
University Extension Office booklet called "Rockets Away." It can be purchased from them for $1.00
I place the students in groups of four and then two students work together to build one rocket.
This makes two rockets per group. Each group has to experiment with the rockets and work together so
that only one variable is changed between them. As a class, we are trying to test many variables so that
when it comes time to build a rocket on their own, they can decide how best to build it to fly the highest.
(Winners get a prize.)
Students sign up for launch day by completing a spreadsheet that has listed the amount of water,
nose weight, total weight, and description and number of fins. During launch, we time the flight from
lift off until it touches down. We then use a formula to calculate the height and velocity and enter the
data on the spreadsheet to make a double graph. H=(t/2) x 16 V= t/2, H/V, x .68 = mph
I made up a quiz from the following board notes. I made a test from the quiz and included
mock rocket data on a graph to test them on the formula. You could also ask them to explain how they
would test a variable using the scientific method.
Notes on board:
I. History
A. 1200's AD - Used in the Middle East. Called "Chinese Fire Arrows"
1. Made of tubes stuffed with gun powder that when ignited, exploded and produced
hot gasses that pushed the rockets into flight.
B. 1687, Sir Isaac Newton published a book of principles which have become known
as Newton's Laws of Motion
C. Only since the 1700's, have rocket experimenters actually understood the scientific
principles behind the motion of rockets.
D. Rockets were used in the War of 1812, which inspired the Star Spangled Banner.
.
II. Newton's Laws
A. First Law
1. Objects at rest will stay at rest, or objects in motion will stay in motion, unless
acted upon by an unbalanced force. (see p. 6-7)
B. Second Law
1. The acceleration of an object is directly related to the force exerted on that
object and oppositely related to the mass of that object. (see p. 8)
C. Third Law
1. For every action there is always an opposite and equal reaction. (see p. 9)

III. Rocket Launch
A. For a rocket to lift off, force must be exerted. (First law)
B. The rate (speed) will be determined by two things: (Second law)
1. The mass (weight) of the rocket
2. By the force produced by the fuel.
C. The reaction, or motion, of the rocket away from the launch pad is equal to and
opposite from the thrust of the engine or nozzle. (Third Law)

IV. Questions people ask NASA scientists about rockets.
A. Do rockets really fly?
B. If rocket engines burn oxygen, how do they work in space?
C. Why do rocket engines have nozzles?
D. Why are rockets so long?
E. If rockets don't fly, why do they have fins?
F. Why are rockets so stream-lined?
G. If rockets fly in space without interference from air or gravity , why must they still be
balanced?

V. Answers.
A. Rockets move without the need of atmosphere (air). (exp. # 5,6)
B. Rockets carry oxygen with them as part of their propellant (solid fuel).
C. The purpose is to increase and direct the acceleration of gases as they leave.
(exp. #7 & a hose)
D. To control the rocket and give it a control system. (exp. # 8)
E. Rockets are stabilized by the effects of air moving over the fins which function as
controls. (exp. # 9)
F. Friction from the Atmosphere (air) will slow the rocket down while it is moving, called
drag and turbulence. (exp. #10)
G. In order for a rocket to remain stable (balanced), the center of pressure and center of
gravity should be no closer than 1/2 the distance equal to the largest diameter of the
body. (exp. # 11)

Note: There are many commercial rocket launchers available. I have plans available where you can
build your own using about $10 worth of common hardware parts. I can email them free of charge. I
can also build one and ship it within the United States for $29.00. Contact me at
JMOORE4@prodigy.net