Now it’s time to take the concepts you have learned and really put them to use.  You are to learn…

Albert Einstein’s Theory of Relativity

Get ready to learn some amazing things about the universe. You are going to grasp concepts that you may at one time thought were beyond your reach. But trust us they are not. You are going to learn things that are going to turn your universe inside out and upside down. The way you view yourself and your place in the universe is forever going to change.

Remember the key is to use your imagination.

We can’t over emphasize this point. Don’t just read the material and have a vague image in your mind. Vividly picture everything we are telling you. When you read a paragraph DON’T go on to the next paragraph until you can clearly see in your mind the image we are describing to you.

It’s not hard!

We have made the images very easy for the mind to see, using things like school buses and baseballs.

You will notice we have not included any pictures or charts to aid our explanations. This is on purpose. This is to help you develop your imagination. You must learn to transfer the words you see to a crystal clear movie playing in your mind. We don’t want to influence the picture. This will only hinder you in the long run. When you learn to make the pictures in your mind your own, you will learn at a pace you never thought possible.

IMAGINE THIS.

You are a kid again. You are riding on a school bus. Disregarding all rules of safety you stand up in the middle isle and jump straight up into the air.

Where do you land?

A few seats forward?

A few seats backward?

If you jumped straight up in the air you land in the exact same spot you were at before you jumped.

Now imagine you are standing on the street and you see the bus coming towards you. This time a friend of yours is jumping on the bus. You can see him or her through the window. At the moment your friend is right in front of you he or she jumps into the air. But notice when he or she lands she is now farther down the road from your perspective. When you are on the bus from your perspective you appear to be jumping up and down. When you are on the street and see your friend do the same thing from your perspective your friend is jumping forward.

Next picture yourself sitting in the school bus and watching the scenery go by as you stare out the windows. It is as if you are sitting still and everything outside the bus is moving even though the bus is actually what is in motion.

If we covered all the windows of the bus would you be able to even tell if you were moving?

No!

As long as the bus stays in uniform motion, which means it stays at a constant speed and direction, no sudden turns, no speeding up or slowing down, then you would not be able to tell if you were moving.

You could continue to jump straight up and down but you would always land in the same place. You could toss a coin up into the air and it would land in your hand. There is absolutely nothing you could do to prove you were moving unless you uncovered the windows and even then it looks as if the outside objects are moving past you.

Now let’s say you’ve determined the bus is moving and that it is moving at 25 miles per hour. Sitting on the bus your body is also moving at 25 miles. Again disregarding safety you stand up in the middle of the isle and walk towards the bus driver, the direction the bus is moving. You walk at 1 mph. Your body is actually moving at a speed of 26 mph, your walking speed plus that of the bus.

25 mph bus speed + 1 mph walking = 26 mph total

When you turn around to walk back to your seat you are now walking opposite, or against, the busses motion and this time you must subtract your walking speed from the bus to see how fast you are actually moving.

25 mph bus speed-1 mph walking = 24 mph total

Also consider this. You are on the bus still going 25 mph you look out the window and a car speeds by at 50 mph. From your perspective the car will only appear to be moving 25 miles per hour.

The bus now comes to a stop and you step off the bus.

The bus drives away at 25 mph. If you are standing still you will see the bus driving away at 25 mph. If you walk towards the bus at a rate of 1 mph you see the bus driving away from you at 24 mph. If you walk in the opposite direction of the bus at a rate of 1 mph and look behind you, you will see the bus driving away at 26 mph.

What all of this tells us is Einstien’s first postulate.

All uniform motion is relative to an observer’s state of motion. There is no absolute well defined state of rest. There is no privileged reference frame.

This does seem counter intuitive, but if a car zooms past a man on the street a 100 mph. It is just as correct for the man in the car to say the man zoomed past me at 100 mph as it is for the man on the street to say the car zoomed past me at 100 mph.

It might help you make sense of it all if you realize there is no one fixed point in the universe with which all motion can be compared. You may think you are standing still on the road. But you are actually hurtling around the sun and the sun is moving around the center of our galaxy. You have to say you are moving relative to something.