Exploding Rockets
Teacher: Mr. Ellsworth and Ms. Klaibi
Date: January 7th, 2019
Subject / grade level: grade 9 academic
Materials:
 Film canister for each group (partner)
 A couple of Alka Seltzer tablets
 A jug to hold a small amount of water
 Hot plates
 Thermometer
 Colored papers, markers and glue sticks.
Lesson objective(s):
The activity introduces the children to:
 A chemical reaction which produces carbon dioxide
 The behavior of gases under pressure
 Factors which influence the rate of the chemical reaction
Differentiation strategies to meet diverse learner needs:
ENGAGEMENT
When the period begins, have a question on the board:
 What is a chemical reaction?
 What is the difference between a physical reaction and a chemical reaction?
 What happens when you have a buildup of gas?
 What would happen when you blow up a balloon without stopping? Why does this happen? (mention the fact
that there is a lot of pressure inside the balloon)
EXPLORATION
 Contrast a model to investigate how this chemical reaction may have occurred. Provide materials so the
students can construct their own model of a exploding rockets. Each group (partner) should receive a film
canister, a couple of Alka Seltzer tablets, a jug to hold a small amount of water, a hot plate, and a
thermometer. Have them use the different colored papers, markers and a glue stick to decorate their space
rocket. Before starting the experiment, ask students to make predictions of what may happen if the Alka
Seltzer and water come together. Ask each group to break the Alka Seltzer tablet into quarters and place one
quarter of the tablet into the film canister. Students then should pour in a small amount of cold water and then
place the lid on the container. They have to quickly turn the container over and wait around 30-40 seconds for
the reaction to happen. They have to record the time it took their rocket to lunch. Once students have seen the
reactions, have them identify the chemical reaction components (reactants and products) and to make some
predictions of what would happen if they changed the size of the Alka Seltzer tablet, the temperature and the
amount of water. Allow students to start the second rounds with changing one variable** and leaving the rest
as constants so they can see the effect each variable have on the reaction. Groups are going to share their what
they observed when changing specific variable (make sure that groups are choosing different variables).
** Variables are: The size of Alka Seltzer tablets, the amount of water, the temperature of water.
EXPLANATION
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Exploding Rockets
 Tell me some of your prediction were before adding the Alka Seltzer tablet (record on your worksheet)
 What actually happened to your rocket when you added the Alka Seltzer tablet and why did this happen
(record so you can make comparisons)
 How long did it take your rocket to lunch? (record your answer in the board) Discuss with the students the
following questions:
 why did it take some groups more time for their rockets to lunch than others? Was this because they
added more water?
Relate their observations to the chemical reaction steps. Use student models to identify and label reactants and
products. Have students work to create definitions for these terms. When the teacher is sure that students have a real
understanding of the terms, formulate a final definition and post on board or chart in the classroom for future
reference. Demonstrate the steps of a chemical reaction and lead students to understand that it is the process that
involves rearrangement of the molecular as opposed to a change in physical forms. Refer to the list generated during
the engagement and have students make connections; they should use the new terms to discuss and explain what they
saw. Help them to understand that this reaction is just one example of many other reactions found around us (let them
name some)
ELABORATION
 Using the same canister but after wiping the edges and cleaning the lids. Ask students to repeat the experiment
again using different variables. For example, using different sized of Alka Seltzer tablets, changing the water
temperature, or changing the amount of water. Students should choose one variable to change and keep the
rest as constants
 Allow students to elaborate based on their finding:
 Why did the rocket take less time to lunch when using smaller size of Alka Seltzer?
 Did the height of the rocket change when changing the size of the tablet?
 What happened to the rocket when using chilled water compared to warm water?
 Do you think it is a good idea to use hot tap water? Why or why not?
 In case we changed the size of the canister and adding more water, do you think the rocket would take
less/more time to lunch?
EVALUATION
 Have photographs representing each process and have students identify and explain why they identified it as
such.
 Have students write their own definition and list an example for each step of the reaction in their science
journals
 Have students try the same experiment but this time using vinegar and bicarbonate of soda. They should write
a paragraph explaining what they observe, and which way was more efficient, using Alka Seltzer tablets or
vinegar and bicarbonate of soda.
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