12.11.08
8th Grade Exam Topic Summaries
UPDATE: Here is the Test Outline ->midterm-review-2008
Pick one of the topics off the list. Fill out the topic review fill-in and post your summary to the blog. Remember, this will help your classmates study for the exam so post quality work. (Please put your topic title in your post)
-Mr. K
December 11, 2008 at 9:46 am
Okay we did Newton’s third law.
For every action there is an equal and opposite reaction. Here are some examples: action-pushing on a wall wearing rollerskates
reaction- you go rolling backwards
the harder you push the further you will go backwards.
action- jumping down on a trampoline
reaction- sends you high in the air
Action and reaction forces are acting on different objects
ROCKET PROPULSION
Action- gases shoot out the bottom of the rocket
Reaction- the rocket goes up
December 11, 2008 at 9:51 am
Summary
Speed is how fast an object travels.
Velocity is the speed and distance of a moving object.
The difference is that the velocity describes the speed and distance.
Speed and Velocity =d/t
December 11, 2008 at 9:59 am
Newtons 2nd law:
Summary
F=M*A
Force= mass*acceleration
December 11, 2008 at 10:08 am
Summary
Newton’s 1st law of motion, also known as inertia, states that an object in motion will remain in motion unless an outside force acts upon it and an object at rest will remain at rest unless acted upon by an outside force.
If a car is advancing forward, it will keep advancing unless an outside force, a car, hits it.
December 11, 2008 at 11:39 am
TOPIC : Gravity
Summary
Gravity is the force that objects exert on each other in order to bring them closer together. An example of this is the Earth pulling down on us, creating weight. It depends on the mass of the objects and the distance between the objects. An object must have a very large mass in order to affect others with its gravity.
Gravity on Earth is always 9.81.
Key Terms
1. gravity
2. mass
3. weight
4. Terminal Velocity
5. Free Fall
Other Topics it relates to
free fall, position/distance, weight, air resistance, terminal velocity
Applications
Can be used to solve gravity problems. Used to keep us down, else we’d float off the Earth.
Memory Aid
Gravity grabs you.
What Mr. Kremer might ask (or has asked).
What does gravity depend on?
What is the gravity pull on Earth?
What is weight?
Word problems with gravity?
December 11, 2008 at 11:46 am
We did Elastic Potential Energy & Thermal Energy
HERES OUR SUMMARY:
Elastic Potential Energy – Energy stored by something that can be stretched or compressed
Thermal Energy- total energy including kinetic and potential energy, of the particles that make up a material; is transferred by conduction, convection, and radiation
December 11, 2008 at 11:49 am
Summary: Free Fall is when the only force acting upon an object is gravity. When something has more mass it has more air resistance. The greater the surface area, the more resistance.
Key Terms and Topics its related to:
1. Air Resistance: It depends on the object’s weight and mass.
2. Terminal Velocity: When air resistance is equal to gravity
3. Gravity: The force that pulls an object towards earth.
What Mr. Kremer might ask (or has asked):
Roberta has a mass of 45 kg. She jumps out of a plane and falls with and acceleration of 9.8 m/s2. What’s the force she feels from gravity?
F = MA F = 45(9.8)
F = -441 N (negative because gravity is bringing it down)
December 11, 2008 at 11:56 am
TOPIC : Simple Machines and Work
Summary
Simple machines are the building blocks of modern machines. There are six simple machines- they are the lever, the pulley, the wedge, the inclined plane, the wheel and axle, and screw. Work is force over a distance. Work is generally done with the help of the six simple machines. The equation is f X d= work
December 11, 2008 at 11:57 am
Conservation of Momentum
Summary
The law of conservation of momentum explains how momentum is conserved and transfered. momentum can be transferred, but can never be created or destroyed. If a collision occurs, the momentum is the same before and after. The momentum from the first object, equally transfers to the second. Momentum is always conserved.
An example is one ball hitting another and the momentum from the first ball transfers to the second ball, and the momentum in the closed system, is the same before as it was after.
December 11, 2008 at 11:58 am
Summary
Stored energy due to position is called potential energy. One type is called gravitational potential energy, which is energy stored by objects that are above Earth’s surface. The BFF for it is PE=MGH. (gravity=9.81m/s) It depends on the height and mass. Kinetic Energy is the energy of motion. It depends on the mass of the object and its velocity. The BFF for it is KE = 1/2MV2. Gravitational Potential Energy and Kinetic Energy are both measured in Joules.
Key Terms
1. Kinetic Energy – the energy of motion
2. Joule – unit of energy (abbreviation-J)
3. Gravitational Potential Energy – energy stored in an object, waiting to be converted
into another type of energy. Also, it is the potential energy of an object raised above earth’s surface.
Other Topics It Relates To-
energy, total energy, PE=mgh, KE=1/2MV2, joules, gravity
Example- What is the kinetic energy of Joey going down a slide at 3 m/s if he has a mass of 10 kg? (HINT: KE=1/2MV2)
BFFS:
PE=mgh & KE=1/2MV2
December 11, 2008 at 12:01 pm
WE DID MOMENTUM:
SUMMARY:
The product of an objects mass and velocity.
FORMULA:
p=mv
KEY TERMS:
1.law of conservation of momentum – the momentum before is equal to the momentum after
December 11, 2008 at 12:11 pm
Topic Review
TOPIC : Unit Conversion (Brock Staskawicz and Enrique Corona)_____________________________________________
Summary: This diagram is used to form different SI units. It helps to make them larger or smaller in the International System. When moving to the right on the conversion line, you move the decimal to the left. When moving to the right on the conversion line, you move the decimal to the left.
Key Terms
1. When moving to the right on the conversion line, you move the decimal to the left.
2. When moving to the right on the conversion line, you move the decimal to the left.
Memory Aid
Mr. Kremer Horribly Died Drinking Chocolate Milk Monday.
What Mr. Kremer might ask (or has asked).
Converting Units
What is the table of Unit Conversion
December 11, 2008 at 12:18 pm
TOPIC : The conservation of energy
Summary: The law of the conservation of energy states that energy can be neither created nor destroyed, so energy is never lost in a closed system. This means that energy can only be transferred from one object to another; the energy cannot just disappear.
December 11, 2008 at 12:21 pm
TOPIC : The Scientific Method
Summary: organized set of investigating procedures that includes the following steps:
Key Terms
1. Problem/Purpose: the question you solved by doing the experiment
2. Research: background information from resources gathered by the experimenter
3. Hypothesis: educated guess
4. Materials/Procedures: what you need to conduct the experiment and the steps involved
5. Experiment: perform procedure and collect data
6. Analysis: analyzing (getting knowledge from your project)
7. Conclusion: confirms/disproves hypothesis, summary of results
December 11, 2008 at 12:24 pm
Chemical energy is energy stored in chemical bonds. You can find chemical energy in your food, your body, and in molecules. There are two Types of nuclear energy, nuclear fission and nuclear fusion. Nuclear fission converts small amounts of mass into enormous quantities Energy. Nuclear Fusion is the process of fusing together two atomic
Nuclei with low masses to form one nucleus with a larger mass. You can find nuclear energy in power plants, the sun, and in nuclear bombs.
December 12, 2008 at 1:30 pm
Topic Review
TOPIC : Position/Distance
Summary: Position is the distance from the origin on a graph. Distance is how far an object moves. Displacement is the distance and direction of an object’s change in motion form the starting point.
Key Terms and Topics its related to:
1. Speed- how fast something goes
2. Distance an object travels per unit of time (v = d/t)
3. Acceleration- rate of change in velocity (change in v/change in t)
4. Instantaneous speed-speed at a given moment
5. Constant speed- speed that doesn’t change
6. Average speed- speed over an entire trip
December 12, 2008 at 1:38 pm
Force/Acceleration
Summary
ACCELERATION is the rate of change in velocity, and FORCE is a push or pull that one body exerts on another. They relate because the greater the force, the greater the acceleration.
F=ma and a=change in velocity/change in distance
You can have a negative acceleration when you are slowing down.
An object can be accelerating if it is moving at a constant speed because the direction is changing.
Key Terms
1. Mass- the amount of matter in an object
2. Velocity- change in speed and direction
3. Unbalanced forces- forces that are not equal but in opposite directions. The objects always accelerates in the direction of the larger force.
4. net force- the sum of all forces
-Lauren and Maggie
December 12, 2008 at 1:47 pm
SI Units (Redone)
Summary
SI Units are units of measurement commonly used around the world. It is also known as the metric system, and is not used in the United States. There are several different units for each measurement.
Key Terms
1. Liter- a unit used to measure volume
2. Gram- a unit used to measure mass
3. Joule- a unit used to measure energy
4. Newton- a unit used to measure force
5. Meter- a unit used to measure distance
6. Second- a unit used to measure time
7. Degrees- measured in Celsius. Used to measure temperature.
December 12, 2008 at 1:51 pm
Summary
Simple machines are used in everyday life and make compound machines. They are six main types of simple machines: 1. Lever 2. Pulley 3. Wedge 4. Screw 5. Inclined plane and 6. Wheel and axel. Work is Force X Distance.
Key Terms
1.lever-seesaw
2.pulley-flag pole
3.wedge-doorstop
4.screw-screw
5.inclined plane- ramp
6.wheel and axel-door knob
December 12, 2008 at 3:31 pm
Topic Review
TOPIC : Roller Coaster Problems!_____andye and
brynn!!! ______________________________________
Summary
A roller coaster problem has three points, A, B, and C. You have to find the KE by doing KE=1/2mv2. Then you find the PE by PE=mgh , m being the mass of the object, g being gravity (9.81), and h being the height of the object. Last you find the TE by adding the PE and the KE together.
Key Terms
1. Potential Energy
2. Total Energy
3. Kinetic Energy
4. Joules
December 12, 2008 at 3:33 pm
TOPIC : _______________________Friction______________________
Summary- Force that opposes motion between two touching surfaces.
Friction depends on two surfaces, what type of surface, and the mass of the surfaces
some examples of friction are the tire marks on the street from a car.
Key Terms
1. sliding- Two surfaces that slide across each other.
2. rolling-Two surfaces that roll over each other.
3.static-The friction between two surfaces that are not moving past each other.
Other Topics it relates to. Newtons second Law of Motion.
Diagram
December 12, 2008 at 3:39 pm
Topic Review
TOPIC: ____________________SI Units_________________________
Summary: the improved, universally accepted version of the metric system that is based on multiples of 10 and includes the meter, liter, and kilogram.
Key Terms
1.International system of units
2.Derived unit
3.Meters
Other Topics it relates to
• Unit conversions
• Calculating distance and velocity
Diagram
Length-meter-m
Mass-kilogram-kg
Time-second-s
Electric Current-ampere-A
Temperature-kelvin-K
Amount of Substance-mole-mol
Intensity of Light-candela-cd
Applications
It makes science units understandable for people around the world!
Memory Aid
S-Science I-Is U-Useful
What Mr. Kremer might ask (or has asked.)
Q. What is the SI Unit for temperature?
A. Kelvin or k