How do you explain Special Relativity to a 13 year old?
Asked by
Rarebear (
25192
)
April 24th, 2016
As asked. You can explain what happens with time dilation and relativistic mass increase, but explaining how and why is much harder.
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7 Answers
@CWOTUS Thanks. I did the gendankin thing yesterday and it didn’t quite stick. I’ll look through the links.
@Call_Me_Jay Thanks Jay. Links are blocked from my current computer from an overactive firewall, but I’ll check them out later.
Is the kid okay at math? Only need one basic equation here.
Imagine a guy on a train throwing a ball straight in the air and catching it again. To someone on the train it looks like it’s just going up and down. But to someone standing by the tracks, it looks like it’s going in a big arc, because it also has the horizontal velocity of the train.
Now imagine the throw is at near light-speed. The person by the tracks would then think the ball is going over the speed of light. But that’s impossible.
Consider v = d/t. If we accept that v is fixed, is the speed of light, and we also accept that d is larger for the guy outside the train than it is for the guy inside the train because of the added horizontal distance, then the only way to make the equation hold is for t to be larger for the guy outside the train than it is for the guy inside. Time dilation occurs.
Ooop, I realize I was posting links about general relativity, not special.
General is about the gravity, special is about the motion (in my limited understanding).
@Mariah‘s answer and @CWOTUS‘s link (see Experiment #3) make the concept of time dilation very easy for me.
Have him or her watch “The Mechanical Universe” on PBS.
@Mariah That’s EXACTLY the analogy I used! :-)
@Call_Me_Jay Yes, I didn’t get into GR because, well 13 year old. I did mention about time moving slower in a gravitational well, but only in passing.
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