Bernoulli 's Principles

Often, I see birds flying. Then, sometime later, I see a plane flying. Birds are light weight, have hollow bones and have to flap or use updrafts to fly. Planes, are huge metal things that have engines and literally, weigh tons. So how does a plane fly? Bernoulli was a scientist who observed that with any fluid, an increase in velocity equaled a decrease in pressure. It applies in actual fluids, like water, and with gas, like what we inhale and exhale. The airplanes wings are shaped so air has to cycle around it, creating low pressure above the wing and high pressure beneath it. That helps the plane to fly. There are always four forces acting on a plane. The planes weight, thrust, drag, and lift. The thrust has to be greater than the drag for it to go forward. For it to go upwards as well, it has to have greater lift than its weight. One of pilots worst enemies is gravity since it always wants to pull down the plane from 5000 feet up. Anyways, planes couldn't fly if they had  a square shaped body. Why? The air wouldn't be able to circulate around it. Bernoulli said that the increase in velocity, for planes its mostly speed instead of direction, meant a decrease in pressure. http://www.centennialofflight.gov/essay/Dictionary/bernoulli/DI9.htm 

Fluids and Pressure

Pressure is simply how much force is applied to one area. Say, you have a cat laying on you lap and you petting it. The cat gets bored and walks away. The amount of pressure went from a large area, its body since it was laying down, to a small area, its paws. Pressure, like speed, acceleration, and momentum, can be increased or decreased. If you wanted to increase pressure on an object, you would either decrease the area you are applying it to, or increase the amount of force you are using. How are fluids related to this? Well, fluids, like everything one this planet, are made up of particles to small to see without a microscope. Water, for example, is made up of two hydrogen particles and one oxygen particle. They aren't as densely packed as a solid object, which is rigid (a good example is a tree. Try moving a full grown one without any tools). Since they are so loosely put together, its motion is random. The particles bounce into each other, away from each other, and go pretty much everywhere. If an object was dropped into a fluid, the object would be acted upon equally from all sides, constantly. Pressure is everywhere, especially in air (duh). At sea level, the air pressures roughly 2.2 pounds of pressure per square centimeter of your body. You wont notice though, since its pressuring equally from all sides. If you have ever gone in a plane, as you get higher in elevation, your ears pop. That's from the air pressure. The higher you get, the more air pressure there is. There is a lower density of breathable air as well, which is why you are in the plane and not outside it. I realize that air isn't related much to fluids, but water(or any other fluid) is a lot denser than air. Similar to the way that the pressure goes up as you get higher in the air, the pressure gets higher the farther down you go. If you went down 3300 feet without any equipment, your lungs would collapse and you would die. Its impossible to get that far down without equipment though, well, unless you were dead. Still, pressure gets higher when the elevation goes up, and gets higher the farther you go down in water.
http://www.school-for-champions.com/science/fluid_pressure.htm link

Density and the Titanic

Density is what makes something float or sink. The Titanic was thought to be unsinkable, until it hit an iceberg, and sank. The Titanic was made so if one level filled with water, it would still float. When the iceberg scraped the sides of the ship, it made holes on several levels. When the water flooded in, the Titanic had the same amount of space as it did before, but the water made it denser.  The water flooded in and first it tilted, then was verticle, then it was too much weight the ship could bear so it broke in half and sank. If the iceberg hadn't hit so many levels, it could have maybe survived with the thousands of people on it. Most icebergs are bigger under the surface. Often, the visible part is only a fraction of the size, thus the expression, the tip of the iceberg. The lower section of the iceberg is completely invisible, so the captain didn't know were it was. It was dark and he couldn't  see the iceberg until he almost collided with it. He tried to steer it away, but the lower decks got hit and let the water in. The water flooding in made it too dense to float. So, it sank, and took hundreds of people to the depths of the Atlantic ocean because there simply wasn't enough life boats.

Density

A heavy wooden block floats in water but a much lighter stone sinks. Why? Well, the stone is denser than the wood. The molecules that compose them are closer together in the stone than in the rock. Think of it like a storage container. One is packed with stuff when the other has a smaller amount of stuff shoved in. The one with more stuff is the exact same size as the one with less stuff, but weighs more. Why? Density. The stuff is much more densely packed into that unit. Density is mass per unit of volume. A stone weighs less than the wood, but is more dense, so it sinks. The wooden block is heavier but is less dense. http://www.physics.ucla.edu/k-6connection/Mass,w,d.htm

Newton Funnies

We saw a video explaining Newtons laws. It was quite funny. The first was a man sitting in a chair saying that an object at rest tends to remain at rest unless acted upon by an outside force then someone slams into him and shows an outside force acting on the person explaining. Then a man is running with an empty box. It shows a message saying Acceleration of an object is inversely proportional to the mass. he comes back running slower with another person in the box and then the man falls off the back. Next, it shows two men hitting each other. The man explaining is back and is saying that for every action, there is an equal and opposite reaction. Then the two men are leaning against each other. One suddenly runs off and the other guy falls to the floor. After that, the same two men run at each other, slam into each other then both fall to the floor. It then runs through credits then does bloopers. At the beginning, it has a warning. 'Do not attempt to do these stunts at home. The stunt men doing this are missing abundant brain cells.'

Conserving Momentum

Momentum is what keeps you moving. Like when you run downhill, you go a lot faster than if you were running ordinarily, even when it evens out you still go fast. What kept you going was momentum. By keeping running down at the mostly steady speed, you built momentum which kept you going after the hill was even. If you hit a person, you would stop and they would go forward. Why? Because you transferred our momentum to them. Same concept with the game billiards. You hit the cue ball in a manner that hits other balls into the holes. You transfer the momentum from the cue ball to the other ones. I realize this might be confusing but heres a link:http://www.grc.nasa.gov/WWW/k-12/airplane/conmo.html

Newtons Laws of Motion.

Sir Issac Newton made the three laws of motion we know of today. His first law was the law of inertia. He said every object was in a state of rest ,or not moving, and would remain so until acted upon. The example you see at http://science.discovery.com/interactives/literacy/newton/newton.html is you hitting an apple with a worm in it. However, if you suddenly stop the apple, the worm will continue moving. Its like when you suddenly slam on the brakes of a car, you hit the seat belt hard. You were moving at the same rate as the car until you suddenly stopped the cars movement. You, were still going until you hit the seat belt. His second law states that if the forces acting upon an object were balanced, the object wouldn't move. If two people were exerting an equal amount of force on say a rope, it wouldn't move. His third law is the most well known. It states every action have an equal and opposite reaction. If I threw a ball on the floor, it would bounce back, with the height it bounces upward with is equal to the force I applied throwing it.  http://www.physics4kids.com/files/motion_laws.html

Forces Simulator

The simulator started with a wooden figure pushing objects.(Sleepy dog, crate, text book, fridge, file cabinet, and mystery item) There was the file cabinet which to move over a surface with friction, needed to be at least 246 net force in either direction.  When the forces are unbalanced it starts moving. However, after the force has been applied then no more is applied, the filing cabnet will stop moving due to friction and its weight. After the filing cabnet simulator, there is a robot moving company. You move another filing cabnet, a textbook and a sleepy dog. You only have a certain amount of energy to move one object. You cant push it too hard or your robot will run out of energy or it will fly off a cliff. Sometimes both. You have the unbalanced force of the robot, and then after friction and the weight of the object it will stop outside the door of a house. Sometimes, you push the object too hard and then have to stop it before it goes off the cliff, thus balancing the forces. Here is the simulator:http://phet.colorado.edu/en/simulation/forces-and-motion and here is another link helping explaining balanced and n balanced forces: http://www.physicsclassroom.com/class/newtlaws/u2l1d.cfm

Combining forces

When some forces are acting upon a object, they are being combined. If two people are pushing against an inanimate object, lets say, one person is pushing with 5N and the other 2N. The object they are pushing would be acted upon with 7N. If the two people are against each other, the net force would be going with 3N in the direction of the person pushing with 5N. If two tug-of-war teams are exactly balanced, both will pull as hard as they can but not moth at all. The net force is 0. By using say 28N on both sides will get you nowhere at all. They are completely balanced. If one side was stronger, the object being acted upon would move in that direction. http://www.philbock.com/APphysics/labs/equilibriumlab.pdf

Balanced and unbalanced forces

Forces like everything else can be balanced or unbalanced. If There was a log floating on water, that would be a balanced force. Since the water pushing upwards and the weight of the log  pushing downwards are equal to each other, its a balanced force. However, if an object was upon it, the weight of the log would be higher than the force of the water pushing up on it. Thus, it would be an unbalanced force and the log will sink a bit into the water. When something is being acted upon by two equal forces, we call it a balanced force. When something is being acted upon by two unequal forces, we call it an unbalanced force. http://www.khanacademy.org/science/physics/mechanics/v/balanced-and-unbalanced-forces

Force: What is it?

Force is used every day every were. But what is it? Force is a push or a pull. If I was playing capture the flag and pulled some ones flag, I applied force while doing so. A more common example is when you push or pull a door to open it. When you push or pull the door, you are applying force. The amount of force you apply can be measured. A unit of force is called a newton or N. If something was 100N, it had a lot more force applied than something with ,say, 5N. http://www.edinformatics.com/math_science/force.htm This also explains t. (Probably a lot better too)