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Relativity Terms

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: 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.

Lesson 4: 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.

acceleration - the rate of changing velocity. There are two common ways of determining acceleration. Acceleration is often calculated with basic kinematic equations and with netwon's second law.

atomic mass - the atomic mass of an element is the mass of a given element. It is often given in units of amu's which is to provide the number of atomic mass units present in the mass of the element.

atomic mass unit (amu) - One atomic mass unit is defined as approximately one of the mass' of a proton (1.66 x 10-27 kg).

c - the speed of light in a vacuum which is a constant value of 300,000,000 meters/second or 186,000 miles/second. This value is constant as viewed by all observers.

hypothesis - an educated guess. A scientific hypothesis must be testable.

L - the length of an object as viewed for a mover by a stationary frame.

Lo - the length of an object as viewed by a mover for the mover.

lifetime - the lifetime of a muon or any other decaying particle is sometimes referred to as half-life. This lifetime is actually the time required of half of a given number of decaying particles to decay. These half-lives or lifetimes range from about 10-22 seconds to 1021 years.

light year - the distance traveled by light in one year. This is approximately 5.9 X 1012 miles or 9.5 X 1015 meters. How did these numbers get calculated?

m - the mass of an ojbect as perceived for a mover by a stationary frame.

mo - the mass of an object as percieved by a mover for the mover.

mass - generally we refer to mass as the amount of matter in an object. It can also be referred to as the resistance an object has to acceleration - inertial mass. That is what is being referred to here. An object traveling with a large velocity will be harder to accelerate than the idential object traveling slower. It does not add matter or swell in size. It is simply harder to accelerate.

mover for the mover - this is a reference to the reference frame in which the object being measured is at rest. For example, if we are measuring the lifetime of a muon, it is the time in the muon's frame that has the actual lifetime of the muon. This would be referred to as the time for the mover for the mover. If we are measuring how far a muon travels in our frame of reference, the actual thing being measured is length within our frame. Therefore, in this case the length in our frame would be referred to as the length for the mover for the mover.

mover by the stationary frame - this is a reference to the reference frame in which the object being measured is moving. For example, if we are measuring the lifetime of a muon, the muon's lifetime is being measured as it streaks by us. The time we measure for it would be the time for the mover by the stationary frame. If we are measuring how far a muon travels in our frame of reference, the actual thing being measured is in the earth's frame of reference, so the length the muon measures in its frame of reference would be referred to as the length of the mover by the stationary frame.

Relativistic Speed - a speed or velocity that is a significant fraction of the speed of light. Relativistic effects are always present, but they are not readily detectable until speeds above 10% c are attained.

Special Relativity - the mathematical and conceptual model of the behavior of spact/time and matter within space/time when that matter is traveling at a constant velocity.

t - the time measured for a mover by a stationary frame.

to - the time measured for a mover by a mover.

theory - a scientific theory is much more than a hypothesis. In daily discussions with friends, a theory and a hypothesis are no different. However, in science, a theory is a synthesis of a huge body of information and experimentation that support the suppositions made in the theory. Scientific theories grow and change constantly making science on of the most dynamic and exciting fields in which to study! If one piece of verifyable and repeatable evidence comes along that dissproves the theory, the theory is changed.

v - the velocity of the mover relative to the stationary observer.

velocity - the measurement of the speed an object is traveling along with the direction of that object. If an object's speed is 50 miles per hour, its velocity could be 50 miles per hour, to the right. For velocity, direction must be included. Constant velocity means the object is maintaining a constant speed and direction. Learn more.

 


© 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.