Aviation
Why are airplane windows rounded rather than square?
To reduce stress concentrations and prevent cracking.
Why is crude oil called "black gold"?
Because it is valuable like gold and is often dark in color.
Why do car engines use oil?
To lubricate moving parts, reduce friction and help remove heat.
Why are race-car spoilers shaped like upside-down aircraft wings?
To generate downforce instead of lift.
Which is stronger in tension: a steel cable or a steel block of the same material and weight?
A cable can efficiently carry tensile loads; its geometry is optimized for tension.
Approximately how much of a commercial aircraft is made from aluminum and its alloys?
Roughly 70–80% for many traditional aircraft designs.
What is the main reason oil pipelines don't simply use gravity to move oil?
Pipelines cover long distances and varying elevations, so pumps are needed to maintain flow and pressure.
What mechanical component allows two shafts to rotate while reducing friction?
A bearing.
Why does a helicopter have a tail rotor?
Mainly to counteract the torque from the main rotor and control yaw.
Can a modern jet engine produce enough thrust to move a fully loaded aircraft weighing hundreds of tonnes?
Yes — that's exactly what it's designed to do.
Why do airplane wings flex during flight instead of staying completely rigid?
Flexibility helps absorb aerodynamic loads and reduces structural stress.
What is an oil refinery actually doing to crude oil?
Separating and chemically processing it into useful products such as gasoline, diesel, jet fuel and other materials.
Why do gears have teeth instead of simply being two smooth wheels touching?
Teeth prevent slipping and maintain a fixed speed ratio.
Why do Formula 1 cars have extremely low ground clearance?
To improve aerodynamic performance and generate downforce, although they must manage airflow and ride-height effects carefully.
Which spins faster: the wheels of an aircraft during cruise or the engine's fan?
The engine's fan spins vastly faster; aircraft wheels stop rotating in flight after retraction.
What is the name of the rotating fan you see at the front of a modern turbofan engine?
The fan.
Why are offshore oil platforms often built with huge steel structures below the water?
To support the platform and resist waves, wind, currents and other environmental loads.
What happens to a metal component when it is repeatedly loaded and unloaded until it eventually cracks?
Fatigue failure.
Why do bridges and skyscrapers sometimes deliberately move in the wind?
Controlled flexibility helps them absorb and dissipate environmental loads rather than resisting them as completely rigid structures.
Why do aircraft tires contain nitrogen rather than ordinary compressed air in many applications?
Nitrogen is dry and reduces moisture-related issues and pressure variation; it also provides consistent tire-pressure behavior.
Why do aircraft generally cruise at high altitudes rather than close to the ground?
Lower air density at altitude reduces aerodynamic drag and improves fuel efficiency.
What surprising everyday products can be made from petroleum besides fuel?
Plastics, synthetic rubber, lubricants, asphalt, paints, fibers and many chemicals.
Why are many mechanical structures designed with rounded corners instead of sharp internal corners?
Sharp corners concentrate stress and can promote cracking/failure.
Why do jet engines have multiple stages of compressors and turbines instead of one huge stage?
Multiple stages allow efficient compression and energy extraction while keeping aerodynamic and mechanical loads manageable.
What happens if you suddenly remove the load from a heavily loaded rotating shaft?
It can experience transient effects such as overspeed or torsional response depending on the system.