Before any of the Alka Seltzer is added to the water all the pressure inside of our rocket is equal which means there is equal pressure on the outside and inside of the rocket, and once the Alka Seltzer enters the water the pressure in the rocket becomes more than the outside pressure. Alka Seltzer has a certain combination of medicine so that you can treat symptoms such as heartburn, upset stomach, or indigestion, The ingredients included in Alka Seltzer are aspirin, sodium bicarbonate, and anhydrous citric acid.
Definition of pressure: the force put on or against an object by something in contact with it
Pressure= Force divided by Area
P=Fa