We have all been amused by the way an inflated balloon behaves when left loose without tying the mouth. This dynamic action has some principles behind it and Isaac Newton, an English scientist, explained why this happens centuries ago. He said that for every action there is a reaction with equal force in the opposite direction. This law of Newton came to be known as his Third Law of Motion and may or may not be found in homeschool programs such as the Apologia science curriculum. However, I love to make this principle come alive in your homes by teaching you some cool rocket experiments.
When we blow air into a balloon, we apply a force on the rubber wall of the balloon. This wall exerts an equal force back. Therefore, as soon as we release our hold on the mouth of the balloon, the wall pushes the air out. Now, as the air is pushed out of the balloon with force, an equal force works in the opposite direction and pushes the balloon in the opposite direction. This is the same principle that is used to launch rockets.
A rocket engine burns fuel, and therefore a large amount of gases are released. The jet of gases hits the ground with a great downward force. Now according to Newton’s third law, an equal force acts on the rocket in the opposite (upward) direction. Therefore a great thrust is created and the rocket is launched into the sky. You may have read about this in the Apologia science curriculum or elsewhere, but I will teach you to have some fun by making this happen in your home.
Seltzer Pressure Rocket: Fill one-third of an empty film-roll canister (preferably transparent) with water. Drop an effervescent tablet (such as Alka-Seltzer) in it. Place the lid and invert the canister quickly on a sidewalk. What happens? The canister is thrown up into the air just the way a rocket is launched.
When the effervescent tablet reacts with water, it releases carbon dioxide gas. This gas builds up in the canister and ultimately sets off a mini-blast. The gas applies downward force on the lid. As a result, an equal force acts on the canister in the opposite direction, launching it. Repeat with two tablets and see what happens.
Please take help from adults while performing this experiment. Also wear protective eyewear. What does this experiment tell you about the amount of fuel it takes to launch a rocket? What do you learn about the amount of force that is required to generate the equal and opposite launching force of the rocket? To get a better idea, watch a video of a real-life rocket launch.
If you’ve been looking for programs such as the Apologia science curriculum or others, you need look no further. You will find my experiments very easy to perform, and the best thing is that the materials you will require can be found around the house. Take a look at another exciting experiment.
Paper-tube Rocket: Make a paper tube by rolling a strip of paper spirally on a pencil.Secure the tube with duct tape at a few places and slide out the pencil. Fold the upper end of the tube so that air does not pass through it and secure it with duct tape to form the nose. Now insert a drinking straw into this tube rocket and blow hard to launch your rocket.
Want some more exciting ideas? Download your free “Homeschool Parent’s Guide to Teaching Science”, filled with great science experiments and activities at the link below.