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Lesson 2: Time Dilation

Lesson 1: Relativity - What is it?

  1. Fermilab's Time Dilation Challenge.
  2. The Basics of Relativity (6 seconds)
  3. The Relativity Game - Challenge what you know!

Note: For Fermilab's Time Dilation Challenge and The Relativity Game, you need Shockwave. You may painlessly Download Shockwave here if you do not have it.

Lesson 2: Time Dilation

  1. The equation.
  2. Where does that come from?
  3. I still don't get it! Give me the basketball analogy.
  4. So what? There's an equation. How do I use the equation in the game?
  5. Practice Problems.
  6. Examples to aid your practice.

Lesson 3 : Relativistic Mass

  1. The equation.
  2. Where does that come from?
  3. I still don't get it! Give me the space pool analogy.
  4. So what? There's an equation. How do I use the equation in the game?
  5. Practice Problems.
  6. Examples to aid your practice.

Lesson 4 : Length Contraction

  1. The equation.
  2. Where does that come from?
  3. I still don't get it! Give me the pole and the barn analogy.
  4. So what? There's an equation. How do I use the equation in the game?
  5. Practice Problems.
  6. Examples to aid your practice.

Give me the basketball analogy.

Immagine that I gave you a basketball and asked you to dribble it straght down and up with enough speed to cover the distance in two seconds. We would hear the basketball hit the ground one time every two second.

This is very similar to the light clock with a light pulse going down and then up in a stationary clock. Also remember that as an observer moving along with the light clock, you would see it go straight down and straight up as if you were at rest.

Now I'm going to ask a second dribbler to dribble a basketball next to you. I'm going to ask her to dribble at an angle instead of dribbling straight up and down. I'm going to ask her to dribble to the same height in the same amount of time.

Question:

As compared to your ball, her ball will cover (more, less than, or the same) distance as her ball goes side to side and up and down.

Question:

To accomplish this different distance in the same amount of time, she would have to dribble (faster, slower, the same) than you.

Play the Basketball Challenge.

Making the analogy with the light clock, the light pulse as seen by the mover for the mover would travel straight down and straight up.

The light clock as seen by the stationary frame for the mover would travel a longer distance as it traveled down and to the right, followed by up and to the right.

Question:

Since light can't travel faster at an angle than it does straight down and straight up, the light as seen by the stationary frame must take (more time, less time, or the same time) to go down and up. Check Einstein's 2nd postulates.

Question:

Another way of saying that is to say that as a stationary frame views one tick of the moving clock (measured as one second by the mover for the mover) as (more than one second, less than one second, or equal to one second) in the stationary frame of reference.

Lesson 2: Time Dilation

  1. The equation.
  2. Where does that come from?
  3. I still don't get it! Give me the basketball analogy.
  4. So what? There's an equation. How do I use the equation in the game?
  5. Practice Problems.
  6. Examples to aid your practice.

 


© Brian Wegley, 1998
Comments and suggestions can be sent by e-mail to
Brian Wegley of Glenbrook South High School..
This page last updated on 7/23/98.