123 Blast off
A rocket is simply a container filled with gas, which is under great pressure. It has a small hole at one end that allows the gas to escape, creating a force called “thrust” that makes the rocket move.
The gas is usually created by burning fuel. In our baby rocket, the gas is created by a chemical reaction between the Alca Seltza and water. When the Alca Seltza starts to dissolve in the water, carbon dioxide gas is produced and trapped in the film canister. When more and more carbon dioxide is created, it takes up more and more space in the canister. When there is not enough space for the carbon dioxide gas anymore, the cap will pop out and hence the rocket launches off!
Why does the rocket launch off when the cap pops out?
Sir Isaac Newton stated the 3 Laws of Motion.
- Object at rest will stay at rest and object in motion will stay in motion unless acted upon by an external force.
- Force is equal to mass times acceleration.
- For every action, there is an opposite and equal reaction.
As explained by Newton’s First Law, the rocket placed on the ground will not launch if there is no force acting on it. When the expanding gas in the canister is strong enough it will pop the cap. The released CO2 will exert a force on the ground. This downward force will result in an equal but opposite force pushing the rocket upwards (Newton’s Third Law). The rocket will only lift off the ground when the thrust is greater than the weight of the rocket.
Why does the Redoxon® effervescence produce gas?
Effervescence is the escape of gas from an aqueous solution. The term is used to describe the foaming or fizzing that results from a release of gas.
In this experiment, the Redoxon® tablet is made of sodium hydrogen carbonate, sodium carbonate, anhydrous, citric acid, anhydrous.
When this tablet is put into water, a chemical reaction occurs which produces carbon dioxide gas which can be observed by the fizz produced.
The essential chemical reaction is:
citric acid + sodium bicarbonate -> water + carbon dioxide + sodium citrate
C6H8O7 + 3NaHCO3 -> 3H20 + 3CO2 + Na3C6HO7
The process of carbon dioxide bubbling out of solution is generally represented by the following reaction, where a pressurized dilute solution of carbonic acid in water releases gaseous carbon dioxide at decompression: