Physical Science, Module 9, An Introduction to the Physics of Motion, Part A

Click for Videos we Watched for Module 9.
Play  Quizlet.  Just scroll down and click on Physical, then scroll to find the Module you want. 
Experiment 9.1, The Importance of Direction
The kids really had fun with this one!  They drew faces on their eggs, and the girls named theirs O'Dale and Leona.  Cousin C named his Breanna.  =)
The experiment called for 2 pieces of stiff cardboard, and I just happened to have a CLEAN pizza box!  So that worked great.  It would have been greater if I'd thought to put pieces of masking tape over the two slits in the V of the box, but the bar was easy to clean off.

Meet the contestants:

First the kids released an egg from the top of one side of the box and caught it at the bottom.  No problem.  Then they released O'Dale and Leona simultaneously with Leona in the lead.  Well, as you can see in the pic, Leona had a false start and was a little ahead of O'Dale, and even though Rebekah made the soft catch, Leona got slightly cracked.  The kids decided O'Dale should have another run at it with Leona.  In the second heat, it was clear that because of her injuries sustained by her false start, Leona was not able to take the pressure in a fair run.

The clean-up crew came and dumped her in a bowl.  She looked so broken!  Well, this just egged O'Dale on!!!  He decided he was invincible!


Next, O'Dale took on my egg, which was very plain and nameless.  In this match, my egg stayed at the bottom while O'Dale came barreling at her. 
 Now my egg had heard of O'Dale,
which you can see by the expression on her face.  She knew he thrived on conquest.
In the end, it was just as she feared; O'Dale triumphed once again.

Last, O'Dale came up against Breanna.  This was a head to head contest, with both coming from opposite directions.  Would he dominate this eggciting battle?
Carefully, the eggs took their positions, anticipating their downward velocity.  Nervously, Breanna eyed the formidable O'Dale.  Like Leona, she had one false start and had to return to the gate.  After several missed attempts, the eggs met in their attack.

Finally, in a perfect head-on collision, O'Dale prevails!!! 

What eggsultation!  What eggsuberance!  O'Dale won in a perfect sweep!

Note: None of these were planned shots.  When I scooped her up, Leona landed in the bowl that way.  We paid no attention to which egg was going next -- just ended up that way!  =) What's funny is the egg that was grinning is the one that won!  lol!

This chapter deals with direction, speed, velocity, and is preparation for math in physics.  We talked about whether an object is moving or not.  If I place a book on the table, we would likely say it wasn't moving.  But to someone on the moon, they would see the earth revolving and say the book was moving.  So, relative to the earth, the book isn't moving, but relative to the moon, the book is moving.
If two objects are moving in the same direction, like 2 people in a car, we do not think of the other person as moving.  But if you move in one direction toward another person, they will say you are moving.
If the egg was moving 0.25 meters per second, and 2 eggs were moving in the same direction, we subtract their speeds.  0.25 m/sec - 0.25 m/sec = 0.  This tells us they are not moving relative to each other.  (In our experiment, Leona apparently was released slightly before O'Dale.) 
If one egg was released and traveled at 0.25 m/sec toward an egg not moving (as in O'Dale and my egg), again we subtract.  0.25 m/sec - 0 = 0.25 m/sec.  The relative speed here is 0.25 m/sec toward each other.
When two eggs were released traveling toward each other (O'Dale and Breanna), going in opposite directions (yes, opposite - as in east and west, etc.), their relative speed was faster.  When objects are going in opposite directions, either toward or away from each other, we combine their speeds.
0.25 + 0.25 = 0.50 m/sec toward each other. 
We know that speed is how fast or slow something is going.  Velocity is not the same as speed.  Velocity is the speed plus the direction.  So we would say the eggs' relative velocity was 0.50 meters per second toward each other.
If one car is traveling south at 70 mph, and another is traveling north in the opposite direction at 55 mph, since they are traveling in opposite directions, you add:  70 mph + 55 mph = 125 mph away from each other.  This is their relative velocity.
If two cars are each traveling north, and one is traveling 55 mph, and the other is traveling 70 mph, since they are traveling in the same direction, you subtract:  70 mph - 55 mph = 15 mph away from each other.   
It is still "away from each other" because the cars are getting further apart.

Wednesday, we plan to go by the cousins house when we go to piano lessons.  They'll drop rocks a ball from their treehouse.  We'll use a stopwatch to get the speed in 10 trials and average these speeds.  We'll then use this speed to calculate the distance from the rail of the treehouse to the ground.  =)
Here's the post.