Dry Ice Rocket Car
Fellow name: Mavis Wong
Grade Level: 10-12
Subject(s): Chemistry
Summary:
In this lesson, students will design a race car powered by dry ice subliming into carbon dioxide
gas, which will help them learn about gas laws and Los Angeles air pollution. The students will
first have a brief introduction on Los Angeles air pollution and smog as the motivation. In the
main two lesson days, the students will be designing and building a simple race car from
construction paper, water bottle, Lego wheels, that is fueled by the thrust of carbon dioxide gas
expanding in the water bottle. In the first day, the students will be designing their car, using a
combination of physics and chemistry to best get the car to meet the competition criteria. The
purpose of the lesson is for the students to use the combined gas law that they learned in
Chapter 12 to design how far their car will go. The cars will be judged based on creativity, how
close they get to the finish line, but most points will go towards whether the calculations in
determining the amount of carbon dioxide gas from the dry ice in providing thrust is correct.
Time Required: Two Full 1-hour Periods and a 10 minutes introduction
Group Size: 4-5 students per group
Cost to implement (for 5 classes with an average of 35 students per class):
 2 bags of 3 lbs dry ice (Smart and Final) - $30
 Stationary and art supplies (Staples) - $60
 Bottles and tape (99cent Store) - $30
 Lego wheel and axles (Lego Store) - $16
 Total: $136
Learning Goals:
1) Students will learn about Los Angeles air pollution
2) Students will learn about the expansion of gases and how to apply the combined gas law
3) Students will learn how to work in groups efficiently to complete lesson objectives
Level of Inquiry:
Guided-inquiry – the students will be given the materials, objectives and will have to develop
their own product to reach best reach the race criteria
Introduction / Motivation:
The brief introduction given the
week before will introduce the Los
Angeles environmental theme of
the lesson: smog. The introduction
will provide brief explanations on
how photochemical smog is
formed and how that is
exacerbated by the Los Angeles
environment and location.
Furthermore, the excessive
amount of chemicals (NOx, VOCs)
released into the atmosphere
does not mitigate the problem.
This will provide the basis of the lesson, and to further engage the students, the introduction
will show the students that in the lesson, they will be designing a car for a competition.
Lesson Background Concepts for Teachers:
The basic background concept for this lesson is the gas laws, specifically The Ideal Gas Law
(PV=nRT) and The Combined Gas Law (P1V1/T1 = P2 V2/T2). The Combined Gas Law helps the
students calculate the expansion of CO2(g) from dry ice temperature (-78°C) to room
temperature (25°C) and the Ideal Gas Law helps the students answer questions about
greenhouse gases on their worksheet.
Procedure:
First “Design” Day
1. Students will use the materials provided and perhaps other materials they bring to
design their race car
2. Calculate the amount of dry ice needed to get their race car to the finish line (given the
volume the gas will fill in the water bottle, the approximate volume of the “exhaust
fume”)
Second “Test” day
1. Complete design if didn’t do so during the first day
2. Weigh dry ice and put ice in car for race
3. Have car judged and results recorded
4. Wrap-up and discuss results and calculations
5. Students will do smog problems to practice gas laws (finish as homework if no time)
Materials List
Each group will need:
 Dry Ice and water
 Lego wheels and axles
 Small bottle with pour spout
To share with the entire class:
 Construction paper



Glue and scissors
Duct tape
Decorative materials (stickers, puffy balls etc.)
Safety Issues:
To ensure not too much pressure builds up inside the bottle, always allow CO2(g) to vent.
Ensure the cap on bottle is off until at start line, and pressurize only for a couple seconds (also
equality in competition).
Lesson Closure:
At the end of the second day when all the students have raced their car, get the class back
together and discuss which car performed the best (and which won the competition). Then ask
them how they think improvements could be made to the car and why. There should be
minimal cleanup in their cars since it’s just water in the water bottles.
Assessment:
Pre-Activity Assessment:
During the smog presentation, I ask the students how much they knew about smog. Most
students were familiar it was a pollutant but not sure about its formation and why it was so
terrible in LA. The worksheet was a good assessment of how well the students understood the
gas laws.
Activity Embedded Assessment:
Depending on how much dry ice the students use, it showed how well the students knew how
to use the gas laws they learned in Chapter 12. Furthermore, the practice problems at the end
of the worksheet will be a good chance for them to practice using the gas laws.
Post-Activity Assessment:
Grading of the worksheets gave me a sense of how well the students understood the lesson
and the gas laws. The students seem to understand the qualitative part of designing the car and
how the expansion of gases propelled the car, but didn’t quite understand how to
quantitatively calculate the amount of gas using the gas laws based on the responses (or lack
thereof).
This lesson is based upon or modified from existing materials:
This lesson is based on a modified version of the chemical reaction powered car. The reaction is
between baking soda (sodium bicarbonate) and vinegar (acetic acid) which will violently react
to form sodium acetate and carbon dioxide. Although the reaction is a good way for the
students to practice stoichiometry, the reaction is very messy and does not fit in with the
curriculum very well. That’s why I’ve decided to modify the lesson and use dry ice, which is a
cleaner alternative and will use the gas laws the students have been learning.
References:
 Kitchen Chemistry – The Chemical Reaction Powered Car:
http://engineering.oregonstate.edu/momentum/k12/march04/index.html
 Balloon-powered car:
http://sciencesquad.questacon.edu.au/activities/balloon_powered_car.html
Attachments:
1. Introduction to Smog Powerpoint
2. Rocket Car Lesson Powerpoint
3. Dry Ice Rocket Car Activity Worksheet
List CA Science Standards addressed:
1. Students know how to apply the gas laws to relations between the pressure,
temperature, and volume of any amount of an ideal gas or any mixture of ideal gases.
2. Students know the random motion of molecules and their collisions with a surface
create the observable pressure on that surface.