Instructor's Notes for Rocket Lab:
Steve Sogo, Laguna Beach High School ssogo@lbusd.org
Introduction: In this lab, students use a stoichiometric mixture of hydrogen and
oxygen to propel soda-bottle rockets 30 to 40 feet into the air. Students calculate
stoichiometric quantities of H2 and O2 gases required for maximum thrust and
produce these gases using suitable reactions. Students also construct aluminum
foil electronic igniters that are used to launch the rockets safely by plugging in a
50-foot extension cord. Upon ignition, each soda bottle will briefly display a
flash of fire, which instantly propels the bottle into the air.
An alternative outcome is achieved if students use juice, water, or milk bottles
instead of soda bottles. Soda bottles can withstand high internal pressures, while
juice/water/milk bottles will explode when internal pressure rises. If a hydrogen
+ oxygen-filled juice/water/milk bottle is ignited, a very loud explosion will be
created, shredding the bottle to bits.
Introductory Video available at Youtube Channel ACR92651: Rockets!!!
http://youtu.be/rFakqDf-Bwc
This lab activity was originally designed to be run as a 1-week project incorporating many
different chemical concepts. The lab can be shortened (possibly to as little as two days) by
cutting out the activation energy and catalysis concepts included in the original instructions.
Scheduling if run as a 1-week project:
Monday:
 Teacher introduces project expectations
 Lab groups assigned
 Each group begins stoichiometric calculations using the bottle they have brought
 Goal is to complete the lab packet through step 4c (if not met during class, students may
complete as homework)
Tuesday:
 Teacher discusses activation energy and catalysis--the energy profile for combustion of
magnesium metal is a good illustrative example.
 Students use Interactive Physics software to model how a catalyst works
 Students continue completing the Rocket Lab packet through step 5d
Wednesday:
 Teacher shows students how to construct aluminum-foil igniters (instructional video
available at: Youtube Channel ACR92651 Rocket Lab: Making Fuses
http://youtu.be/eaVyCz5Bqro)
 Aluminum foil, index cards, scissors and rulers supplied for student use.
 Students build at least two igniters and test at least one igniter using a 12-volt
transformer. Goal is to produce an instant spark upon plugging in the transformer
 Students produce step-by-step instructions for launch day. Students must translate the
information contained in the lab packet into a protocol--What must be done first? (fill
bottle and trough with water!) What next?? Instructor can provide a step-by-step
document for students who cannot accomplish this on their own (sample procedure
attached at the end of this document)
Thursday/Friday
(At the author's school, Thursday and Friday are 100-minute block periods, allowing ample time
for the generation of gases and the launching of nine rockets per class. If only short periods are
available, the author recommends filling the bottles with oxygen on Thursday, leaving the bottles
partially filled with water so as not to create an explosive mixture within the bottles. Then
students will need to efficiently complete the filling of each bottle with H2 and proceed to launch
the rockets on Friday.)
 Teacher shows instructional video that discusses how to generate oxygen gas "perfectly"
by packaging the potassium iodide catalyst (Youtube Channel ACR92651 Rocket Lab:
Making Gases http://youtu.be/hyMHLUUH1Zg).
H2O2
H2 + O2
KI





Students set up water displacement troughs and generate O2 gas, collecting the oxygen in
soda bottles using displacement of water (the oxygen should fill 1/3 of the volume of
each bottle)
After filling each bottle 1/3 full of oxygen, students generate H2 gas using the reaction of
calcium with water (or a suitably active metal with acid--Mg turnings + excess 2-molar
HCl works well). The hydrogen is collected in the soda bottle until all the water in the
bottle has been displaced.
The bottles now are ready for launch. Instructional video for launch procedures =
Youtube Channel ACR92651 Rocket Launching http://youtu.be/28zOejqRe6s
A ring stand with several rings of varying diameters works well as a launch pad. Extra
rings are recommended, in case one is breaks.
For rocket ignition, the author recommends using a pair of extension cords, one at least
50-feet in length. Rocket ignition is initiated by plugging the two extension cords
together, transmitting power to a 12-volt transformer. Ignition should be instantaneous.
If ignition does not occur, the cords may be unplugged to allow trouble-shooting (most
common cause of failure is a bad igniter or bad electrical connections). Instructional
video for wiring a Radio Shack 12-volt transformer: Rocket Lab: Wiring a 12-volt
Transformer http://youtu.be/GGV1UGl-1iA
Lab Set-up requires:
At each lab table:
 Water trough
 125 mL flask with #5 stopper
 250 mL flask with #6 Stopper
 Tygon/rubber tubing (about 18” length) with dropper tip
At the buffet table
 3 bottles of 10% hydrogen peroxide solution (Instructor prepares
10% peroxide by diluting 1-part Baquacil Shock and Oxidizer with 2parts water (e.g. 250 mL Baquacil + 500 mL distilled H2O).
Instructor should make 30 mL of 10% peroxide per rocket/bomb.
 The igniters that students built previously (kept safely in a box overnight)
At the weighing stations:
 Weighing paper (3 x 3" or 4 x 4")
 Potassium iodide catalyst
 Later on, Calcium metal will appear next to the scales (Flinn calcium (C0009)
recommended)
Bacquacil Shock and
Oxidizer (30% H2O2)
Helpful Hints for Launching:
 Have students sign up for a particular launch order (like a batting order)
 When going outdoors to launch, bring:
 Launch pads with various sized rings (two ring stands recommended in case of wind)
 Big cardboard box to act as a windbreak
 Small box containing:
o Scissors
o Masking tape
o Transformer
o Several patch cords with alligator clips
o Sharp Pencil (useful for separating tip of aluminum foil igniter)
o Some paper towels (for drying off launch pad)
o Voltmeter? (can be useful for troubleshooting electrical problems)
 Medium box for trash pickup/windbreak
 Test that the transformer is "live" by using a voltmeter (or tapping the alligator clips together
to observe sparking) prior to trying to launch any rockets
 Keep all students at a safe distance (approximately 50-feet) except for those who are setting
up their rocket.
 One member of each student team should be designated to be "on the cord". This student
should clearly demonstrate that the extension cords are NOT plugged in while students (and
teacher) are setting up the launch pad.
 Plug your ears if igniting a gallon jug! The explosion can be deafening (and may set off car
alarms nearby)
 REMIND STUDENTS THAT SAFETY GLASSES MUST REMAIN ON ALL DAY
LONG!!!!!!
 There will be messes made--students must clean up their lab stations.
 Lab packet due on Monday
Assignment #114: Launching Rockets using Secret Fuel #1
The “secret fuel” is a mixture of hydrogen and oxygen
Overview: In the next lab block, you will be making hydrogen rockets using plastic bottles with volumes
between 1 and 4 Liters. You will fill the bottles with a mixture of hydrogen gas and oxygen gas in an
appropriate ratio. When ignited, the reaction will produce H2O gas at a very high temperature. The hot
molecules will generate a propulsive force (or the bottle will simply blow up).
Note: filling out these pages IS your write-up for this lab. Do your work neatly and
completely.
1. The first thing to determine is the appropriate ratio of hydrogen and oxygen to use in your rocket. You
need an explosive mixture to launch your rocket. A mixture too rich in hydrogen will burn quietly like a
Bunsen burner instead of igniting explosively. A mixture too rich in oxygen will produce suboptimal
thrust. A proper stoichiometric mixture will produce maximum power for your rocket.
The unbalanced equation for the propulsion reaction is as follows:
H2 (g) +
O2 (g) 
H2O (g)
If you balance the equation shown above, you will know the correct MOLE RATIO of hydrogen to
oxygen needed to achieve maximum propulsive force.
2. Use a 1-liter graduated cylinder to accurately measure the total volume of your bottle.
Using the mole ratio of H2 to O2 that you discovered from your balanced equation, you can start to figure
out how much hydrogen gas and how much oxygen gas you will need to fill your plastic bottle. In the
space below, sketch a picture of your bottle (label total volume) and draw a line showing what fraction
of the bottle you will fill with hydrogen and what fraction you will fill with oxygen. Then convert these
fractions into actual volumes of hydrogen and oxygen (in liters). Note: try to discuss how the MOLE ratio
compares to the VOLUME ratio that you have sketched in your picture.
3. Use the IDEAL GAS LAW and your picture above to calculate how many MOLES of hydrogen and how
many MOLES of oxygen you will need in your plastic bottle. Also give a one-sentence explanation for
why 22.4 L/mole is NOT a valid ratio to use for this experiment. Hint: what does STP actually mean?
Assignment #114: Rocket Lab (continued)
From page one, you know how much hydrogen and oxygen you need for your rocket, but you will have to
GENERATE these gases by running chemical reactions. This page discusses production of oxygen gas.
4. OXYGEN gas can be generated from the decomposition of H2O2. The unbalanced equation is:
H2O2  H2O + O2
H = -190 kJ/mol
The reactant in this reaction, hydrogen peroxide, is thermodynamically unstable. Rearranging its atoms to
form water and oxygen gas will lower the potential energy of these atoms. This reaction is extremely
slow at room temperature unless a catalyst is added. You will use the salt potassium iodide (KI) as a
catalyst to hasten this reaction. Note: When running the actual reaction, a small scoop of the catalyst (about 0.7
grams ) will be “packaged” in weighing paper and then added to the hydrogen peroxide solution. You will place a
stopper on the reaction flask and then shake to allow the catalyst to come out of its package. This method should
enable you to collect 100% of the gases created in this reaction.
a) Balance the equation shown above and use stoichiometry to calculate the MASS of hydrogen peroxide
needed to generate enough O2 for your rocket. Hint: your calculation starts with the number of moles of O2
you calculated in step #3.
b) The hydrogen peroxide that you will use to generate oxygen gas will be provided as an aqueous
solution of hydrogen peroxide. The solution contains 10% hydrogen peroxide by mass (the other 90%
being water). Use your number from part (a) to calculate how many grams of this SOLUTION you will
need to use. If you don’t know how to make the calculations required here, I suggest you start by drawing a
picture representing a composition of 10% hydrogen peroxide and 90% H2O. Then label the fraction of the solution
that you KNOW (the mass of H2O2 calculated in part (a)).
c) Assuming that the 10% peroxide solution has a density of 1.0 g/ml, convert the grams you calculated
in (b) into milliliters of solution.
d)** (complete after Tuesday’s lesson—in which your instructor will teach you some new ideas) Assume the sketch below
represents the energy profile for the UNCATALYZED decomposition of hydrogen peroxide.
i. In the sketch of the uncatalyzed reaction, place labels that designate positions of: H2O2, H2O + O2,
ACTIVATION ENERGY (Ea), and H VALUE for the reaction (H value is shown at top of this page).
ii. In the space to the right, sketch a profile for the catalyzed decomposition of hydrogen peroxide. Then
EXPLAIN HOW the catalyst helps the reaction proceed at room temperature.
Explanation for ii:
PE
PE
Uncatalyzed Reaction
Catalyzed Reaction
Assignment #114: Rocket Lab (continued)
This page discusses production of hydrogen gas.
5. Hydrogen can be generated in many ways. You will use the reaction shown here:
Ca (s) + H2O (l)  H2 (g) + Ca(OH)2 (s)
ΔH = _________
a) Balance the equation shown above.
b) Calculate a H value for the reaction (in KJ/MOLE) knowing that the reaction is EXOTHERMIC and
produces 10.4 kilojoules of heat for each GRAM of calcium that reacts. Write the calculated value in the
space provided above.
b) Use stoichiometric calculations to determine the MASS of calcium and VOLUME of water needed to
produce enough hydrogen for your rocket. Be neat!!!! You should know how much H2(g) you need!!!!
c) The amount of water calculated in (b) is the amount that will actually react with the
calcium you are weighing out. In your reaction, you will use EXCESS water. Circle two of
the choices below to identify reasons why it is wise to add excess water when you run this
reaction. Note: when you run the reaction, you will want to use a LARGE excess (as large as your
reaction flask permits). In the box, SKETCH your reaction flask containing a large excess of water.
i. extra water will create extra hydrogen
ii. extra water will create more heat in the reaction flask
iii. extra water will keep the reaction flask cool
iv. extra water will reduce the amount of air that goes into the rocket
Sketch of Rxn flask
d) The calcium you will be using is a very reactive metal. Even while inside its jar, the outer surface of
the calcium will be oxidized to some extent (forming CaO). This reduces the amount of actual calcium in
the lumps that you will be using. How should you correct for this problem?
6. Two final questions (to be completed after the rockets are launched):
i. Discuss the role of the ignition spark in the combustion rxn that launches the rocket. Sketch an PE
energy profile in the space to the right and use this profile to discuss the term “activation energy”.
Combustion Rxn
ii. What is your explanation for why the bottle actually lifts off? Note: the ignition of the hydrogen/oxygen mixture
generates VERY HOT gas molecules with lots of kinetic energy. What do you think these hot molecules will do?.