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Activity

Rocket powered by baking soda and vinegar (demonstration)

Summary: 
An adult sets off a rocket powered by the chemical reaction of baking soda and vinegar. Students figure out how the rocket works.
Science content (2016 curriculum): 
Chemistry: States of Matter, Properties of Materials (K-7)
Chemistry: Atoms, Molecules (3-7)
Chemistry: Chemical Changes (2, 7)
Earth/Space: Extreme Environments, Space Exploration (6)
Materials: 
  • baking soda
  • tissue to wrap baking soda in
  • vinegar (can also do with lemon juice)
  • rocket
  • cloth for clean up
  • water to rinse out rocket
  • open site to set off rocket
  • sturdy flat base to stand rocket on if grass is bumpy
  • optional: molecule models - 3 red oxygen atoms, two white hydrogen atoms, one black carbon atom and 6 bonds for each student/student pair
Procedure: 

What happens when we mix baking soda and vinegar/something sour? It makes a gas. Baking soda and vinegar in this bottle with the cork on will trap gas in the bottle. The pressure will build up, until it pushes the cork out.
It is a rocket powered by a chemical reaction.

Pour 300ml vinegar into the bottle.
Add a couple of teaspoons of baking soda to the tissue, and twist the ends to package it, but so that it is narrow enough to fit through the mouth of the bottle.
Make sure that you are away from the students, then push the baking soda package into the bottle. Cork the bottle, then stand it up for take off.
Stand back. Even if it takes a little time, the tissue will eventually disintegrate and release the baking soda into the vinegar, and set off the rocket.
If you think gas escapes more slowly (around the side of the cork, for example) and the rocket will not fly, kick it over with your foot before reaching down to take it apart, and reset it.

With older students, model the chemical reaction that powers the rocket:
Give each student a model of HCO3 (baking soda) and H (the atom that makes vinegar acidic). We started with these in the rocket.
The baking soda and vinegar molecules react and rearrange to make two new molecules. Ask students to figure out what these molecules are, giving them the hint that one of them is water.
The products of the reaction are water (H2O) and carbon dioxide (CO2).
Carbon dioxide is a gas, and as more and more of it is made by the chemical reaction, the gas builds up in pressure until it blows the cork out of the bottle.
Once the cork is released, the gas can escape by shooting out of the bottom of the rocket. This force propels the rocket upwards.

A rocket that goes to space acts on the same principal of action and reaction: the exhaust is expelled out of the back of the rocket, and this force is countered by a force on the rocket that propels it upwards.

Notes: 

Purchase molecule models online at Indigo Instruments https://www.indigoinstruments.com
One set to model the chemical reaction above requires:
2 hydrogen atoms #60110E (1 Hole 17mm White Atom) 45 cents each in 2017
3 oxygen atoms #60200E (2 Hole 105 Degree 23mm Red Atom) 59 cents each in 2017
1 carbon atom #60400E (4 Hole tetrahedral 23mm Black Atom) 67 cents each in 2017
6 bonds #61013E (Molymod Double-Triple Bonds) 19 cents each in 2017
Get at least one set per student pair and several extra atoms of each type and 10 or so spare bonds.
For 15 sets plus spares you'll spend about $100 with tax and shipping.

Grades taught: 
Gr K
Gr 1
Gr 2
Gr 3
Gr 4
Gr 5
Gr 6
Gr 7
Teaching site: 
CAGIS (Canadian Association for Girls in Science)
Dorothy Lynas Elementary
Eton Arrowsmith Camp
Fraser Elementary
Gordon Elementary Science Club
ingridscience afterschool
JEMZ+ After school science
Shaughnessy Elementary