Learning standards covered by these activities:

Major Understanding
5.1q According to Newton’s Third Law, forces occur in action/reaction pairs. When one object exerts a force on a second, the second exerts a force on the first that is equal in magnitude and opposite in direction.

Alka-Seltzer Rocket Materials:

• black 35 mm film canisters
• Alka-Seltzer tablets
• Water
• A flat surface that can get messy

Procedure:

1. Break an Alka-Seltzer tablet into quarters
2. Put about 1 teaspoon of water into the bottom of the film canister
3. Drop the tablet in and quickly seal the top of the canister with the lid
4. Place the canister upside down on a flat surface and wait about 30 seconds
5. The rocket should launch a meter or two in the air with a loud popping noise

Explanation:
As the Alka-Seltzer mixes with the water it releases carbon-dioxide gas. The gas is confined to a closed space, so therefore builds up a lot of pressure. Eventually the pressure is so great that the top blows off forcing the canister upward. This is a good demonstration for Newton’s 3rd law. For every action, there is an equal and opposite reaction. The gas is pushing up on the top of the canister and the canister is pushing down on the gas.

Balloon Rocket Materials:

• Two chairs
• Tape
• String
• Balloons
• Soda Straws

Balloon Rocket Procedure:

1. Set up two chairs about five meters apart
2. Tie a string to one end of the chair
3. Blow up a balloon and hold the end closed, do not tie the end
4. Tape a straw along it’s vertical axis
5. Thread the string through the straw and tape the other end of the string to the second chair
6. Let go of the end of the balloon and watch the balloon race to the other end of the chair
7. You can add some more fun by having the students design their own balloon using construction paper and tape or change parameters such as the amount of air blown into the balloon or the size of the hole that the air is allowed to escape, to see which student get make the best (quickest) balloon rocket

Explanation:
Just like the Alka-Seltzer rockets, the walls of the balloon are pushing in on the gas and the gas is pushing out on the side of the balloon. All the forces balance until you let go of one end of the balloon, and then the escaping air pushes the balloon forward while the air gets pushed back by the wall of the balloon. It’s Newton’s Third Law again!

Reinforcement Activities:
Have students measure the height of a rocket, time of flight, or analyze if the rocket follows projectile motion. Talk about real world situations and how air resistance affects the flight of an object by having the students design their own rockets. Model rockets and water rockets have excellent applications beyond Newton’s third law and are a lot of fun for student and teacher alike.

Related Products

• Water Rocket and Water Rocket Launcher - Safely and inexpensively introduce students to model rockets. Shatterproof plastic rocket runs on only water and air.
• Alpha III E2X - An excellent beginner level model rocket.
• Launch Pro Altimeter - Accurately record the trajectory of your entire flight and download data directly into your computer of PDA. Designed for use with water powered or solid fuel rockets.
• Soda Bottle Physics Kit - Grab your students’ attention with four easy, safe and entertaining experiments: Hero’s Fountain, Tornado Tube, Water Rocket, and “Squidy” Cartesian Diver. Each supplied with all components and instructions.
• The Launch Pro Ultimate Bottle Rocket System - Unlike any bottle rocket system you’ve ever seen, the Launch Pro system offers a complete range of accessories for converting your used plastic soda bottles into powerful single and two-stage rockets.

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