Everything is relative to everything else.

If you’re going 5kph, you’re doing that relative to the earth which is spinning at 1,600 kph and travelling round the sun at 100,000 kph 

 No, because a 5 year old would immediately recognize the lie. 

 A bouncing ball on a train is quite easy to understand.

Why the very same ball following the very same motion over the very same time period in front of 2 people travels a different distance is much harder to intuit, even for a 5 year old.

People never exist in 2 places at once, so relativity is unintuitive.  But 2 things always exist in 2 plaves at once, so relativity is helpful in navigating our realm. 

 Which lie? Science does not and cannot lie: it's the pinnacle of objectivity. 

 So you mean the science objectivity like in Covid/Corona-times? 

 Exactly! Good example! 

 You're sealed in an elevator and are weightless.  SCARY!

You don't/can't know whether your elevator is accelerating towards an object (as in freefall) or not (as in empty space).  YOUR IMMEDIATE FATE DEPENDS ON IT!

Everythinhg *outside* the elevator determines the elevators acceleration, based on how much those things are accelerating near the elevator.  SO DON'T EVER GET STUCK FEELING WEIGHTLESS IN A SEALED ELEVATOR! 

 Einstein himself seemed to have figured these things out through the eyes of a 5yo 🤣