Parachute ejection systems that sense barometric pressure for activation need a vent to the outside in their compartment because:

Parachute ejection systems that sense barometric pressure for activation need a vent to the outside in their compartment because:

• A. This hole allows excessive ejection charge pressures to vent
• B. The hole is used to give outside air pressure readings
• C. The hole vents internal air pressure as the rocket gains altitude to prevent internal air pressure from prematurely separating the model
• D. The hole allows easy verification that the battery is installed

Answer: (B)

The key idea is that a parachute ejection system using a barometric sensor needs to measure the ambient air pressure, not the pressure inside its own housing. The vent to the outside lets outside atmospheric pressure reach the sensor so it can read the actual altitude-related pressure. If the interior were sealed, changes inside the housing—such as gas from the ejection event or temperature shifts—could skew the reading and cause premature or late deployment. By providing a direct path to outside air, the system can reliably detect the ambient pressure and trigger at the intended altitude. Other options miss the central point: venting to relieve internal pressure from the ejection charge isn’t the primary purpose, and the hole isn’t about battery verification.

The key idea is that a parachute ejection system using a barometric sensor needs to measure the ambient air pressure, not the pressure inside its own housing. The vent to the outside lets outside atmospheric pressure reach the sensor so it can read the actual altitude-related pressure. If the interior were sealed, changes inside the housing—such as gas from the ejection event or temperature shifts—could skew the reading and cause premature or late deployment. By providing a direct path to outside air, the system can reliably detect the ambient pressure and trigger at the intended altitude.

Other options miss the central point: venting to relieve internal pressure from the ejection charge isn’t the primary purpose, and the hole isn’t about battery verification.