--Videos we watched for Module 10.
--This is an
excellent resource with interactive links:
Newton's Physics Notebook
--Find relevant links at
Physics4Kids.
Laws of Motion is a good one for this Module.
--Play
Quizlet. Just scroll down and click on
Physical, then scroll to find the Module you want.
--
Michelle's post.
The Greek philosopher
Aristotle (384-322 B.C) said that the natural state of of an object is for the object to remain at rest; that if something is moving, it "wants" to stop moving.
Around 2,000 years later,
Isaac Newton (1642-1727 A.D) introduced the three laws of motion that are now the basics of physics.
These new ideas were not easily accepted!
Today we learned about
Newton's first Law of Motion - the Law of Inertia.
" An object in motion or at rest will tend to stay in motion or at rest until it is acted upon by an outside force."
Things "want" to stay as they are. If they are at rest, they "want" to stay at rest. If they are moving, they "want" to stay moving.
Until they are made to move, or are stopped by hitting something, or by friction, or by the downward pull of gravity. If you think there is no friction when a ball rolls on your kitchen floor, think about different kinds of flooring. They all have different degrees of friction.
For our
First Inertia Experiment 10.1, we placed an index card on top of a glass with a penny on the card. The kids took turns flicking the card and letting the penny fall into the glass. Initially the card and the penny were at rest. They "wanted" to stay that way. When they flicked the card, they applied force to the card, but not the penny. The force caused the card to move, but not the penny, which dropped into the glass because of gravity. Cousin
C was the card retriever -- it kept going into the floor. =) It "wanted" to go sailing across the room, but the outside force of gravity pulled it down.
Second Inertia Experiment 10.1 Again today, the kids had eggs to name. =) I gave them each an egg, and told them to name it something that started with a
B, not telling them I had boiled eggs and raw eggs. They were cold - I boiled them last night so they wouldn't know the difference. They had to keep drying off the
condensation so the markers would draw on them. Then they spun the boiled eggs around, and if they did it fast enough, the egg stood on end while spinning. Then I told them to very briefly, stop the egg and quickly let go. This did nothing but stop the egg from spinning.
Then I gave them each a raw egg, and told them to name it something that began with
R. I wasn't going to tell them
just yet these were raw, but after seeing them with the boiled eggs, I felt I'd better! This time Rebekah's (boiled) egg did not fare as well as
O'Dale! → →
These eggs did not spin well, but did so very slowly.
But if they were able to get them going a little, it would show a great example of Newton's first law. I told them to get the eggs to spin, and stop and release them quickly. The raw eggs began to spin again on their own.
This is because the fluid inside the egg kept spinning.
If an object is at rest, it wants to stay at rest unless acted on by an outside force.
If an object is moving, as the fluid of the egg was, it wants to keep moving unless acted on by an outside force. Stopping the egg briefly was not enough to immediately stop the liquid from spinning.
Newton's law also shows us why we get dizzy when we spin around. In the semicircular canals in your ears, there are tiny particles called "otoliths," or "ear sand." These particles rest on tiny hairs that sense their position, and sends signals to your brain. When you start spinning, so do the otoliths. That tells your brain you are spinning. When you suddenly stop, the otoliths keep spinning because of inertia, telling your brain you are still spinning.
Experiment 10.2, How Well You Understand Newton's First Law: I showed the kids a plastic bowl with about ¼ cut out. I told them we would start at one side of the cut, and roll a marble around inside the upside-down bowl, so that the marble would come out the other side. I taped it onto a piece of paper and had each kid draw where they thought the path of the marble would be. Cousin
C drew the green line, Cousin
A drew the red line, and Rebekah drew the brown lines (!) Cousin
C was right. His line was
juust a little crooked. =)
This is also because of Newton's first law. Objects in motion tend to stay in motion
in a straight line, following the path of least resistance. Once free from the bowl, the marble rolled straight.
Friction is the reason Newton's first law goes against your everyday experience. When you roll a ball, it doesn't roll forever. Aristotle would say the ball "wanted" to stop. Newton would say the ball stopped because of an outside force such as friction, gravity, and maybe other forces like wind resistance, or another object that it runs into.
Our
experiment 10.3 about
Friction called for a rough board and a smooth board. I meant to get Travis to bring something from work or from his Dad's house, but didn't get
a round tuit. hee hee!
Soooo... we just used a leaf from our table! Rough side, smooth side. =D

Across one end of the rough side of the board, the kids put a small block of wood from our
SiamMandalay Links game, a rock that was smooth on one side, a cube of ice, and a small block eraser. They raised the board higher and higher, noting the height of the board when each object slid down. When we flipped the board over and started the experiment with the smooth side of the tabletop, the ice slid down almost immediately. So they decided to dry it off, and start over. Then the ice stuck to the tabletop and stayed there until after the block of wood had slid down! ha.
Guess the ice being slightly wet was better after all. You can see that despite the fact that gravity was pulling these objects down, friction prevented them from immediately sliding down the board. You can also see that different objects have different amounts of friction.
We talked about friction in preparation for learning about the second law of motion,
the force of an object is equal to its mass times its acceleration. Force = (mass) · (acceleration) Friction always comes into play when you are calculating force. We went over this a little today, and will finish the module next week.
Just want to brag on JohnDavid a little. =) A couple of days ago, I had been studying, and I mentioned Newton's Laws of Motion. I heard him mumble, "Yeah, objects in motion tend to stay in motion..." as I was walking into the other room.
Hmm! Guess teaching
him this stuff this won't be hard! =D
If you've read (or scrolled!) this far, here's something for you to enjoy. =D