POP Rockets: An Introduction to Chemistry and review of Experimental Design
PART ONE – Observing the System
MATERIALS:
 One empty 35mm plastic film canister and lid.
 Fizzy table
 For alka-seltzer type – use one-half tablet
 For denture type – use one whole tablet

Water
 10 mL graduated cylinder
 Safety goggles
PROCEDURE:
A. Put on safety goggles to cover your eyes! Do not take them off until you have completed the lab
– including clean up.
B. Remove the lid from the film canister and use a graduated cylinder to put 10 ml of water into
the canister.
Do the next 2 steps quickly
C.
D.
E.
Drop the fizzy tablet into the canister and quickly snap the cap onto the canister (make sure that
it snaps on tightly.)
Quickly put the canister on the lab table and step back. Do not disturb the system for at least 3
minutes. If it does not ‘pop’ in that time, there is probably a leak in the system. Carefully
remove the lid, clean out the canister and try again.
Clean up your lab space and return to your assigned classroom seat.
ANALYSIS:
1.
2.
3.
Record your observations from this part of the lab.
Did your observations match the observations of other groups? If so – why? If not – why?
Observations can be considered qualitative or quantitative.
Qualitative observations use your senses to observe the results.
(Sight, smell, touch, taste and hear.)
Quantitative observations are made with instruments such as rulers,
balances, graduated cylinders, beakers, and thermometers. These
results are measurable.
4.
5.
a. Give one example of a qualitative observation that you or someone else made in this lab.
b. Give one example of a quantitative observation that you or someone else made in this lab.
c. Which are better – qualitative or quantitative observations?
Briefly describe what happened to cause the canister to pop. If you are unsure, do the
background reading .
Chemistry can be defined as “the study of matter and its interactions”. How is this pop rocket a
good example of chemistry? (Make a claim – site evidence – provide an explanation)
BACKGROUND READING:
The BASICS - There's nothing like a little rocket science to add some excitement to the day. When you add the
water it starts to dissolve the fizzy tablet. This creates a gas called carbon dioxide. As the carbon dioxide is
being released, it creates pressure inside the film canister. The more gas that is made, the more pressure
builds up until the cap is blasted up. This system of thrust is how a real rocket works whether it is in outer
space or here in the earth's atmosphere. Of course, real rockets use rocket fuel.
MORE DETAIL – Rockets move by expelling fuel in one direction to move in the opposite direction (Newton's
third law of motion). For our pop rockets, the thrust force comes from a pressure build-up caused by a
chemical reaction. When the antacid tablet is placed in water, many little bubbles of gas are created. What
exactly is going on?
Antacid tablets contain aspirin, sodium bicarbonate (NaHCO3) and citric acid (H+). Bicarbonate compounds
react with acids to form carbon dioxide and water. Something similar happens in other fizzy tablets.
HCO3 + H+  H2O (liquid) + CO2 (gas)
Figure 1. The basics of a pop-rocket
In an antacid tablet, the bicarbonate and citric acid are solids and so the H+ and HCO3-1 ions are not free to
move, collide and react. When plopped into water, the citric acid and sodium bicarbonate dissolve, freeing the
ions to react. This results in the formation of carbon dioxide gas.
The bubbles go up, instead of down, because they weigh less than water. When the bubbles get to the surface
of the water, they break open. All that gas that has escaped from the bubbles pushes on the sides of the
canister. Eventually, something has to give ─ the canister literally pops its top. All the gas rushes up and out,
pushing the lid up and away. The lid (rocket) travels upward with a force that is equal and opposite to the
downward force (Newton's third law of motion). The amount of force is directly proportional to the gas
expelled from the canister and how fast it is expelled (Newton's second law of motion).
PART TWO – Task
As part of the Palmer Aeronautics Team you have been asked to design an experiment that tests
what fuel combinations are best at launching a pop rocket towards the ceiling.
•
After conducting the fairest test possible, you will write a clear report about your results so
that others can copy your work exactly.
•
Since there are several types of “fuel” available for you to work with, you will need to
record your data carefully so nothing is confused.
Use the guidelines below to help you do your best scientific work.
Materials available:
•
Film canisters (different types)
•
Alka seltzer tablets
•
Vinegar
•
Hot and cold water
 Stop Watch
Discuss as a team: THIS LAB IS WORTH 50 POINTS Please take your time and follow directions
1.
What do we already know about the materials we have available?
2.
In order to keep our study “fair,” we can only change one variable. Which variable do we
want to change? Why?
3.
What will we measure during this experiment? How will we measure it correctly?
4.
How can we work together as a team to get the job done well?
Design your experiment: Include the following items in your report
Title: Clearly state your research question/problem. This format may help: What is the effect of
¬¬¬¬___IV__ on ___DV___?
Hypothesis State what you think will happen, and why you think that. This format may help:
If the ____(IV)______is changed from ___ to ___, then the ___(DV)___ will ____ because…
Variables: Identify and discuss your variables. Include the independent and dependent variables as
well as the controls.
Materials and Method: List all the materials you will use and describe what you will do step-by-step
in your experiment. Try to be so clear that any student in the class would be able to repeat your
experiment exactly just by reading your method.
Data Table: Yikes, this is the hard one. Set up a data table to collect the data you measure. Be sure
to include a title, labels
Title
DV (unit of measure) DV (unit of measure) DV (unit of measure)
Trial 1 Trial 2 Trial 3
(IV – change #1)
(IV – change #2)
(IV – change #3)
Claim: Write your conclusion for the lab. Make a claim, (this will be your hypothesis) but you will
need to support it with evidence and offer your best explanation.Testing the System – Designing an
Experiment
PROCEDURE:
1. Work in your lab team to write ONE testable question and a hypothesis to go along with it.
Draw a single line under your independent variable and a double line under your dependent
variable.
2. Document the procedure you plan to use and design a data table to record your data in. Be sure
to address any safety issues with your plan.
3. Get your work checked for safety and initialed by your teacher.
4. Collect your materials and safely conduct your experiment.
5. Clean up your lab and write a conclusion (claim, evidence, explanation).
Note to students: If you need help knowing what to write, refer to the “Designing an Experiment”
packet and/or your PowerPoint Notes and/or your scientific methods vocabulary sheet.
Design Your Own Experiment
PLAN
Now that you’ve considered the possibilities and made some decisions, it is time to
actually write up your plan. The plan will earn points according to the checklist
AND will be scored on the rubric provided. Some reminders:
Title: 10pts
Clearly state your research question / problem.
What is the impact of __(IV)__ on the __(DV)__ of __(system)__ ?
Variables: 6pts
Identify your variables (IV, DV, CV)
The independent variable is…
The dependent variable is…
The following variables will be controlled…
Hypothesis: 4pts
State what you think will happen --- and why you think that…
If the __(IV)__ is changed from ___ to ___ then the __(DV)__ will
_____ because …
Materials: 2pts
List the materials you will use – be specific – include amounts and type
Procedure: 6pts
Describe what you will do with step-by-step instructions and/or a labeled
diagram. Another student in this class should be able to follow your
procedure to repeat your investigation.
Data Table: 12pts Create an organized data table to record your data
Remember to
 title your data table
 place the independent variable in the rows - with one row for each
different way you are changing the independent variable.
 place the dependent variable in the columns – with each column
representing a different trial - include units when applicable
(title)
(DV)
(unit)
Trial 1
(DV)
(unit)
Trial 2
(DV)
(unit)
Trial 3
(IV – change #1)
(IV – change #2)
(IV – change #3)
DO
Once your plan has been approved by your teacher, gather your materials, do your
lab – collect your data, and clean up. The lab will earn points according to the
checklist AND will be scored on the rubric provided.
CLAIM 10pts Write your conclusion for your lab. Make a claim – support it with evidence and
offer your best explanation. The conclusion will earn points according to the checklist provided.
POP ROCKETS MYP RUBRIC
Criterion B: Inquiring and Designing
Focus: The focus for this lab will be on describing a problem, setting up a hypothesis and stating your variables, and
how they can be manipulated.
At the end of this lab our goal is to have you at the 3-4 Achievement Level
1. describe a problem or question to be tested by a scientific investigation
2. outline a testable hypothesis and explain it using scientific reasoning
3. describe how to manipulate variables, and describe how data will be collected
4. design scientific investigations
Achievement
Level
0
1-2
3-4
5-6
7-8
Level Descriptor
Task Specific Description
The student does not reach a standard
indicated by any of the standards below.
The student is able to:
I. state a problem or question to be
tested by a scientific investigation with
limited success
II. state a hypothesis
III. state the variables
IV. design a method, with limited success
The student is able to:
I. state a problem or question to be
tested by a scientific investigation
II. outline a testable hypothesis using
scientific reasoning
III. outline how to manipulate the
variables, and state how relevant data
will be collected
IV. design a safe method in which he or
she selects materials and equipment
The student is able to:
I. outline a problem or question to be
tested by a scientific investigation
II. outline & explain a testable hypothesis
using scientific reasoning
III. outline how to manipulate variables,
and outline how sufficient, relevant
data will be collected
IV. design a complete and safe method in
which he or she selects appropriate
materials & equipment
The student is able to:
I. describe a problem or question to be
tested by a scientific investigation
II. outline & explain a testable hypothesis
using correct scientific reasoning
III. describe how to manipulate the
variables, and describe how sufficient,
relevant data will be collected
IV. design a logical, complete & safe
method in which he or she selects
appropriate materials & equipment


you try to identify a problem or question, but it’s not very
clear
when you “state” something, you give it a name, but not an
explanation or details




at this level you add clarity to your ideas
your hypothesis includes some of your thinking & reasoning
you clarify how you will use the variables
you mention data you will collect and how you will work
safely


now you are adding more detail to your written work
you use if, then, because and are more clear about the
variables
you partially develop a data table
your method is safe and well planned




you include a lot of detail about what you are testing, what
you predict will happen, how you will control or change the
variables
you develop a complete data table as well as a clear method
that is safe & efficient