does anyone know what causes turbulence on an airplane?

The plane traveling through water vapor like clouds or even just rain. Wind Gusts cause it too, like if your driving a car, sometimes you get pushed by the wind.

differences in air currents put different amounts of pressure on the wings of the plane, causing it to jerk suddenly sometimes, while at other times it moves smoothly through the air.

Yes, some people do know what causes turbulence on an airplane.

What causes turbulence?
Turbulence is the up-and-down air currents that help to mix the air in the troposphere. It is usually mentioned in the context of airplane flights, where these air currents can feel like "bumps in the road" while flying. Turbulence can occur in the lowest part of the troposphere during the daytime when heating of the sun causes convective mixing of the air. Once the airplane rises above this turbulent "boundary layer", the air becomes smoother. But other processes can also cause these up- and down-drafts. One example is convective clouds. If an airplane must fly through a thunderstorm, these updrafts and downdrafts can be very strong. There is also "clear air turbulence", which can also become very strong. This usually occurs near jet streams, where rapidly changing wind speeds with height can combine with an unstable air layer to cause "waves" of up and down motion in this air layer

Aircraft fly through large masses of air at high speed, and sometimes they move between masses of air that have different wind directions and speeds.  When they move from one mass to another, the aircraft is pushed slightly in a different direction, up, down, right, or left.  This is turbulence.

It's similar to driving a car at high speed over a hilly road.  As the car reaches each hill or valley, it moves up and down.  In an airplane, it's air, rather than pavement, but the principle is the same.

Turbulence is harmless to aircraft, although it can bother passengers.  Even severe turbulence usually does no harm to the aircraft, but it can toss passengers around inside the cabin and injure them, which is why you should always wear a seat belt in an airplane (just as in a car).

The actual movements of the aircraft are quite small, but they tend to be fast and sudden because the aircraft is flying at high speed.

Turbulence is most common where there are clouds, rain, fog, etc., but it can occur anywhere.  Turbulence in thunderstorms is dangerously violent, and for this reason, airliners always, always steer clear of thunderstorms (rain and clouds are fine, but not thunderstorms).

turbulence is caused by uneven heating of the ground causing air above to be different densities causing the amount of lift to change as the plane passes through

Turbulence is caused mostly by change in Temperature. When a the Temperature is warmer, more air molecule's air needed to move through the engine to move the plane.  When the air is colder air molecule's are closer together and the engines works less.  The turbulence is the change of the engine from warmer air to colder air or colder air to warmer air.

Hi ,pressure over the wings dude.. air density temperature changes..Best Regards Steve