LESSON 1: ROCKETS
Frameworks Addressed In This Lesson
Technology/Engineering: Engineering Design
*Identify the five elements of a universal systems model: goal, inputs,
processes, outputs, and feedback
*Demonstrate methods of representing solutions to a design problem, e.g.,
sketches, orthographic projections, multiview drawings.
*Explain how such design features as size, shape, weight, function, and cost
limitations would affect the construction of a given prototype.
*Given a transportation problem, explain a possible solution using the
universal systems model.
* Identify and describe three subsystems of a transportation vehicle or
device, i.e., structural, propulsion, guidance, suspension, control, and
support.
* Identify and explain lift, drag, friction, thrust, and gravity in a vehicle or
device, e.g., cars, boats, airplanes, rockets.
Physical Sciences (Chemistry and Physics): Motion of Objects
*Graph and interpret distance vs. time graphs for constant speed
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Day 1:
Getting Started
Overview
After this lesson, students will be able to:
Identify the five steps of a universal systems model: goal, inputs, processes,
outputs, & feedback (GIPOF)
Today students will complete a survey entitled What Do You Know About Space? to
assess their prior knowledge in the field of space flight technology. The survey
consists of 5 picture identifications, 5 true/false statements, and one open-ended
question. After the survey, the teacher will introduce a long-term Moon observation
project that has the students track the Moon over one cycle, drawing what they see
each day. The class will end with an overview of tomorrow’s bottle rocket activity,
including an introduction to the 5 elements of a universal systems model and the rules
of safety and conduct for the launching activity.
Background
Long-term project assignment: Observing the Moon
Later in this unit, students will learn about the phases of the Moon and the laws
of planetary motion. Today students will be assigned a long-term project that requires
them to observe the Moon each day for an entire cycle (about a month). If a few days
of observing are lost due to weather conditions it is not a big loss; have the students
leave those days blank or draw what they think the Moon should look like on those
days based on previous observations. There are worksheets in the student activity
booklets on which the students are to draw the Moon as they see it each day (or
night). These observations will be used later to create a flip-book of the Moon phases
and to calculate the distance to the Moon (optional). The instructions for the long-term
project and a table of approximate rise and set times for the Moon can be found in
Appendix B.
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Bottle rocket activity:
Tomorrow the students will be going outside to launch rockets made out of
empty plastic soda bottles. Today it is important to introduce the 5 elements of a
universal systems model: goal, inputs, processes, outputs, and feedback (GIPOF). This
model is going to be used throughout the unit to give the students a working knowledge
of the engineering process. Below is an overview of what each element entails.
Goal:
For the system at hand, the goal is to launch a bottle rocket as far as
possible.
Inputs:
The input is the command given to a system. For example, by pumping air
into the water in the bottle rocket, you are commanding the build-up of
pressure and the subsequent launch
Processes:
The process is the action of the system, combining the resources
(people, information, materials, tools and machines, energy, capital,
and/or time) and produces results. For example, energy is stored in the
“fuel” (water); the machine is the bottle rocket; people (the
teacher/students), information, time, and materials work together to
make the rocket launch and fly.
Outputs:
The output is what is produced -- the actual result. Hopefully the output
matches the input command, i.e., we hope the rocket launches when we
pump air into it. There can be multiple outputs.
Feedback:
Feedback is information about the output that can be used to change it.
For example, if you find that a rocket with 400 mL of water travels
farther than a rocket with 100 mL of water, you can adjust the water
level in your next attempt to optimize the distance traveled.
During the bottle rocket activity, certain safety precautions should be taken. The
activity should be done in a large open outdoor area away from all buildings, cars, and
windows. Students and teachers should stand well behind the launch pad. It is a good
idea to count down each launch so as to make all participants aware of the launch.
People standing close to the launch may get wet as the water streams out of the
rocket during launch, so it’s a good idea to make sure students are dressed
appropriately for this.
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What You Need
For each student:
A copy of the student activity booklet
Preparations
1.) Photocopy the student activity booklet so that there is one for each student in
the class.
2.) Familiarize yourself with tomorrow’s activities so that you are able to give the
students a brief introduction today.
Activities
1.) Have the students complete the What Do You Know About Space? survey (pg 1
of student activity booklet). Students will take this survey again at the end of
the unit, so you should collect the completed surveys and keep them for
comparison. Answers can be found in Appendix A (pg 97).
2.) Explain the long-term Moon observing project to the class. A copy of the
project is provided for the teacher in Appendix B (pg 107) and on page 4 of the
student activity booklet.
3.) Give the students a brief introduction to tomorrow’s rocket activity, especially
the five elements of a universal system and the safety rules (pg 14 of student
booklet).
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Day 2:
. . . 3, 2, 1, Blast Off!
Overview
After this lesson, students will be able to:
Make scientific predictions and test the effects of changing variables in a
system
Today students will be launching bottle rockets made out of empty 20 oz. soda bottles.
Their goal is to make their rocket travel the farthest by testing the effects of
different water levels in the rocket and launch angle of the rockets.
Background
Rockets work on the simple physical principle known formally as Newton’s 3rd Law of
Motion: for every action there is an equal and opposite reaction. On a very basic level,
a rocket is a pressurized gas chamber. As gas escapes through a small opening at one
end, the rocket must be propelled in the opposite direction as stated by Newton’s 3rd
Law. The force that propels the rocket is called thrust.
Our toy rockets will be made out of empty plastic soda bottles. Each bottle will be
filled to some level with water and corked shut. A bicycle pump will be used to add air
to the water and build up pressure inside the bottle. When the pressure gets high
enough, water will be forced through the opening of the bottle, the cork will pop out,
and the rocket will take off.
Modern rockets use either solid or liquid propellants (or a combination of the two). The
propellant is both the fuel and an oxidizer, which is an oxygen compound. Oxygen must
be present in order for the fuel to burn. The difference between car/airplane engines
and rocket engines is that rocket engines must carry their own oxygen so that they
will work in the vacuum-like conditions of space. Car and airplane engines are able to
use oxygen from the surrounding air (sometimes called air-breathing engines).
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What You Need
For the class:
6 identical empty soda bottles (all from the same brand of soda so that they
are equivalent in shape, weight, etc.)
1 bicycle pump (with pressure gauge if available)
1 “launch pad” with at least 6 different launch angle capabilities; a suggested
design can be found in Appendix C (pg 112)
6 rubber stoppers for the soda bottles
1 permanent marker to mark off water levels
1 measuring tape for measuring flight distances
1 measuring cup marked off in mL
3 stop watches (or wrist watches with seconds)
Preparations
1.) Mark each empty soda bottle with 6 water levels: 0, 100, 200, 300, 400, &
500 ml.
2.) Fill each bottle to one of the 6 levels.
3.) Place a rubber stopper into each bottle – be sure to push each stopper in
the same amount.
4.) Fill a container with enough water to refill the bottles during the launch
activity.
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Activities (This activity should be done outside!)
1.) Have the students read the background info on pg
15 of their activity booklets.
2.) Bring the students outside to an area with plenty
of space (and away from any cars or windows). Be
sure to bring extra water with you to refill the
rockets.
You may get wet
3.) Give 1 bottle rocket to each group (you can have
them pick numbers out of a hat to minimize conflict
over who gets which water level in their rocket).
4.) Before launching, have the students predict which
rocket will go the farthest and why. They should write their responses in the
space provided in their activity booklets (pg 16).
5.) To prepare for launch, insert the bicycle pump needle into the cork of the first
bottle rocket. You may need to make a small hole with a nail or tack first.
6.) Place the rocket on the “launch pad” with the stopped end facing down.
Someone should hold the stopper with the launch pad – the bottle will fly off and
leave the cork behind.
7.) Assign three students to be timers and have them stand parallel to the
trajectory of the rocket at fixed distances from the launch pad. You may need
to do a test flight first to determine where to position these students. Each
student should begin timing when the rocket takes off and stop timing when the
rocket passes by his/her location. The last timer will stop his/her watch when
the rocket lands. Each of these times and distances from the launch pad should
be recorded in the student activity booklets.
8.) Make sure everyone is clear of the launch path. Have a student from the first
group pump air into the rocket until it takes off. **You may get wet**
9.) When the rocket lands, have the students from that group take the measuring
tape and measure the distance from the launch pad to the landing site and share
the measurement with the rest of the class. In their lab activity booklets, the
students should record the distance traveled by each group’s rocket.
10.) Launch the remaining 5 rockets.
11.) Refill the bottles to the level of water that the farthest-traveling rocket had in
it to begin with. Repeat steps 2-9, this time varying the launch angle between 0°
and 90° using the guide on the launch pad.
12.) Save the bottles for activities later in the week.
CAUTION!
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Day 3:
Plotting A Course Of Action
Overview
After this lesson, students will be able to:
Graph scientific results, i.e., distance vs. time
Today you will discuss the results of yesterday’s rocket experiment with the
students. The students will also have two graphing assignments: one of a fictional data
set and the other of their results from yesterday.
Background
What determines how far a bottle rocket travels? Yesterday the students launched
rockets, controlling two variables: water level and launch angle. Several things should
have been noticed. The bottle with no water in it shouldn’t travel very far or very
straight. Too much water also compromises the distance capability of a rocket. Bottle
rockets are propelled by the release of built up pressure inside the bottle. By pumping
air into the water, pressure is added until the cork can no longer hold the water inside
the bottle. By Newton’s 3rd Law of Motion, every action has an equal and opposite
reaction. As the interior pressure of the bottle blows the cork off backwards, the
bottle must react with a forward motion. You should have found that there is an
optimal amount of water that produces the longest rocket flight. If you have too little
water, the rocket runs out of “fuel” too quickly. If you have too much water, you are
carrying extra mass that will not be used as “fuel.”
Launch angle also plays a role in determining how far your bottle rocket will travel,
though not as crucial a role as the amount of water. Ideally, a 45° inclination will give
the longest trajectory. In the real world there is air resistance and the uncontrollable
factor of wind to consider, so there may be some deviation from 45°.
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For the graphing exercise, students will be asked to first graph distance vs. time for a
fictional data set with constant velocity. A constant velocity graph of distance vs.
time should be a straight line with constant slope since velocity = distance/time and
slope is change in y divided by change in x. Next, the students will graph the data they
collected themselves during the bottle rocket launch. When comparing the two, they
should see a difference in the shapes of the resultant curves — this is because the
rockets do not travel at constant velocity, they start from zero velocity and
accelerate. At the highest point of its trajectory (apogee), the rocket will reach zero
upwards velocity and fall back down to the ground.
What You Need
No materials required.
Preparations
No preparations necessary.
Activities
1.) Discuss the results of yesterday’s rocket activity. Ask the students to come
to their own conclusions about what makes the rockets travel farthest.
2.) Have the students graph the fictional data set provided in their activity
booklets (pg 18) on the grid next to the data table.
3.) Have the students graph the data they took yesterday during the rocket
activity and compare it to the graph of the fictional data.
4.) Discuss the graphing results with the class. Allow the students to give their
opinions as to why the 2 graphs look different. The goal is to get them to
realize that the rockets accelerate when they are launched and do not travel
at constant velocity.
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Homework Assignment #1
In their activity booklets (pg 20), have each student sketch additions they would make
to their bottle rockets in order to make them fly farther. You may suggest things
such as fins or a nose cone, but encourage them to come up with their own creative
ideas. Have the students accompany their drawings with a short write-up of why they
chose such additions and how those additions will aid the flight length of their rocket.
Also have the students decide how much water they would put in their bottle and at
what angle they would launch their rocket.
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Day 4:
Time To Rebuild
Overview
Today students will implement the changes they sketched for last night’s homework
assignment.
Background
Long fins may improve the stability of the rocket during flight, thereby increasing the
flight distance slightly, but the difference may not be noticeable. A nose cone, while
aerodynamic, will probably have little effect on the flight distance as well. Adding a
payload (something to be carried) will most likely just add extra mass, and therefore
decrease the distance a bottle rocket will travel. As you can see, making these
additions to the rockets will probably not make a noticeable difference in how far the
rockets travel. The purpose of this exercise is to emphasize to the students that it is
the water level that is most important in determining how far a water bottle rocket
will fly.
What You Need
For the class:
Construction materials such as: cardboard, construction paper, tape, glue,
scissors, paper clips or washers (for added mass), markers, etc.
Preparations
1.) Gather appropriate construction materials.
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Activities
1.) Divide the class into their groups and give them back their bottle rockets from
earlier in the week.
2.) Have the students share their design ideas with their group mates and
construct the additions to their rockets.
3.) You may want to have more advanced students design disks of various sizes to
attach to their rockets so that they may examine the effects of different
levels of drag on the rocket flight.
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Day 5:
Rocket Launch, Take Two
Overview
After this lesson, students will be able to:
Write a scientific lab report based on their predictions, testing, data
collection, graphing, and redesigning.
Today students will test their redesigned rockets and write up a lab report about the
week’s activities.
Background
No background necessary.
What You Need
For the class:
Redesigned student rockets
Bicycle pump
“Launch pad”
Rubber stoppers
Measuring tape
Stop watches (or wrist watches)
Lesson 1: Rockets
From Day 2
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Preparations
Same as Day 2 except that you should fill the bottles to the levels chosen by each
group.
Activities (This activity should be done outside!)
CAUTION!
You may get wet
1.) Take the class outside.
2.) Set up the bicycle pump in a clear area away from
buildings, cars, and windows.
3.) Assist the students in launching their rockets as
you did earlier in the week.
4.) Again, have the students measure the time and
distance traveled by each rocket and record the
measurements in their activity booklets (pg 21).
They will need these numbers for comparison.
5.) If time permits, go back to the classroom and
discuss the results of today’s launches.
Homework Assignment #2
Have the students follow the format provided in their activity booklets (pg 22) to
complete a lab report about the week’s activities. Based on their designs, they should
also suggest changes that could be made to construct the ultimate flying machine.
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