Why does preassure affect the flight of a bottle rocket?

Pressure affects the flight of a bottle rocket because it determines the force of the water and gas expulsion that propels the rocket upward. When the pressure inside the bottle increases due to added air or gas, it creates greater thrust when the nozzle is opened, resulting in a more powerful launch. Conversely, if the pressure is too low, the rocket may not generate enough force to achieve significant altitude. Therefore, optimal pressure is crucial for maximizing the rocket's performance and flight distance.