Download 8th Grade Physical Science Class Notes

8th Grade Physical Science Class Notes
Antonio Bravo
5/12/11
3 period
Chapter 12
Rotation
-axis rotation over 1 day
-tilted about 23 degrees
-results in...
-day and night
-2 high tides and 2 low tides
-ocean circulation
Revolution/Orbit
-Elliptical over 1 year
-results in
- seasons, climate, and even weather
- ocean circulation pattern
Gravity,mass, and Distance
-Gravity Attracts a lll subjects toward on another
-If mass increases force
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Tessa Davis
5/12/11
the earth, moon and the sun: ch 12
Rotation
-Axis of rotation over 1 day
-tilted by about 23-degrees
-results in...
-day and night
-2 high tides and 2 low tides
-ocean circulation
Revolution/orbit
-elliptical over 1 year
-results in....
-seasons, climate, and even weather
-ocean circulation patterns
Gravity,mass and distance
-gravity attracts all objects toward one another
-if mass increases, force also increases
-if distance increases, force decreases
Gravity and the moon's inertia
- Newton concluded there are two forces keeping the planets in orbit: gravity and inertia
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Hannah Blevins 3/30/11 Chapter 14
The Solar System
Main Idea
-Unbalanced forces cause motion
-What is the role of gravity in forming and maintaining the shapes of the planets, the
stars, and the solar system?
-The sun is one of thousands of suns in the Milky Way Galaxy
-Suns Differ in size,color, and temperature
-Astronomical units and light years both can be used to measure distance between planets
-the stars are the source of all light in the solar system
100,000 A.U.=1 L.Y.
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Ch 14 3/30/11 Cali Vance Science 2`
The Solar System
Main Ideas
-Unbalanced forces cause motion.
-What is the role of gravity in forming and maintaining the shapes of the planets, the
stars, and the solar system?
-The sun is one of thousand of the sun in the Milky Way Galaxy.
-Suns differ in size and color and temperature
-Astronomical units and lights years both can be used to measure distance between
planets
-The stars are the source of all light in the solar system
Kepler's Law
-First law: planets move in ellipses
-Second law: when planets get close to the sun they move faster
-Third law: if you know how long it takes a planet to orbit the sun you can calculate its
distance from the sun
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Nic Freiri 3/29/11 period 6 Ch. 13
Homeostasis; the ability of an organism to keep a stable internal environment regardless
of the weather, ect. ie sweating & shivering.
circulatory-blood & carrying Respiratory system- breathing& burring food.
Integumentary system- skin& protection Muscular system - muscle & moment Endocrine
system- Hormones & communication nervous system- nerves, sensing & responding
Excretory- kidney
Skeletal system movement, protection, calcium & phosphorous storage, Blood cell
production
Aly Dembry 3-16-11Chapter 11 Science Period 3
Pascal's Principle
-When force is applied to a confined fluid, the change in pressure is transmitted equally
in all directions to all parts of the fluid
Bernoulli's Principle
-As the speed of a moving fluid increases, the pressure exerted by that fluid decreases
Chapter 11 What to Know
-Predict if an object will float or sink
-Unbalanced forces produce motion
THE END
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Ryan Deng 3/16/11 2nd period Science
Predicting Floating and Sinking
- knowing that water is one you can predict if an object will float or sink
- less than one will float, more than one will sink
D=m/v
- density will increase if Mass increases or Volume decreases
- density will decrease if Mass decreases or Volume increases
Buoyancy
- the buoyant force acts in a direction opposite to gravity to make an object have less
weight but the same mass
- weight < buoyancy = floats
- weight > buoyancy = sinks
weight = buoyancy = hovers
Archimedes' Principle
- the buoyant force acting up on a submerged object is equal to the force of the weight of
the volume of liquid the object displaces
- when the weight of the water displaced by the object equals the buoyant force on the
object, it will float
Pascal's Principle
- when force is applied to a confined fluid, the change in pressure is transmitted equally
in all directions to all parts of the fluid
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Zane Marte Chapter 11 fluid mechanics
period 3
3/15/2011
Fluid Pressure
Gas or Liquid
"In a fluid the molecules exert an equal pressure in all directions."
We live at the bottom of 100km of fluid air which exerts a pressure of 14.7 pounds per
square inch.
This pressure is exerted equally in all directions: up and down and is said to be
"balanced."
Unbalanced forces produce motion
Air pressure decreases with altitude.
Liquid pressure increases with depth below surface.
Air pressure is measured with a barometer.
Liquid pressure is measured with a hydrometer.
Density & Buoyant Force
Density is mass/volume
D=M/V; write circle formula on sheet if not there.
Water is one: Density of water= 1g/cm3.
One gram per cubic centimeter.
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3-15-11.
Fluid Pressure
-Gas or Liquid
-In a fluid the molecules exert an equal pressure in all directions
-we live at the bottom of 100km of fluid air which exerts a pressure of 14.7 lbs/square
inch
-this pressure is exerted equally in all directions; up and down an dis said to be balanced
-unbalanced forces produce motion
Fluid Pressure Cont
-Air pressure decreases with altitude
-Liquid pressure increases with depth below surface
-Air pressure is measured with a barometer
-liquid pressure is measured with a hydrometer
Density and Buoyancy
-Density is mass/volume
- D=M/V write circle formula on sheet if not there
-Water is one; Density of water = 1g/cm3
-One gram per cubic centimeter
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Period 3 Cameron Korb 1-12-11
Velocity=D/T with direction
Acceleration
-Change in speed or direction is called direction
-increase in speed is acceleration, decrease in speed is deceleration
-an object can still be acceleration even if its speed is constant if it changes direction. For
example the seats in a Ferris wheel are accelerating even though the speed may be
constant because they are moving in a circular motion
Acceleration Equation
-So... Acceleration is change in velocity per unit of time. Heres the formula:
-A=V1-V2/T1-T2=Meters/sec squared=M/sec squared
-V1 is the initial velocity and V2 is the final
-T1-T2 is the total time elapsed
-T1-T2 is always positive (can't go back in time)
-if V1-V2 is positive the object is acceleration
-V1-V1 is negative the object is decelerating
(note this is not how the book presents it
Graphing Acceleration
-if there is a curved line on a d-t graph the object is either accelerating or decelerating
-smile=accelerating
-frown=decelerating
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1/11/11 Holly Saner P. 3
Average Speed Equation
- Average speed = Total Distance/ total time.
- Average S = total d/total t
- Sa = Dt/Tt/ Dt= 32km + 13km= 45km
- Tt = 2hr + 1hr = 3hr
- S = 45km/3hr = 15km/hr
Instantaneous Speed
- The speed at which an object is moving at a particular point in time.
Slope...
-The slope of a d vs. t (d-t) graph is the rise over the run (y over x).
- The slope of a d-t graph represents the speed.
Vectors
- A vector is a quantity that has both a magnitude and a direction. Example: 45 mph
Northwest.
Example l
v
o
/
o---> o
o
\
o
Velocity
- Velocity and speed are different!
- Velocity is speed in a given direction.
IMPORTANT; Changes in velocity may be due to change in speed, change in direction,
or both!
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Period 2. Leilani Bellamy 1-11-11
instantaneous speed
*The speed at which an object is moving at a particular point in time.
Graphing speed
** look in your notes
slope
*the slope of a d vs. t (d-t) graph is the rise over the run. (y over x).
*the slope of a d-t graph represents the speed.
* a vector is a quantity that has both a magnitude and a direction. examplr 45 mph
northwest.
Velocity
* velocity nag speed are different!!!
* velocity is speed in a given direction
*IMPORTANT : changes in velocity may be due to change in speed, change in
direction , or both!!!
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1/10/11 Holly Saner
Science Notes: Ch. 9; Motion & Energy
Position & Motion
- An object's position is defined by a reference point and a reference direction.
- A reference point is something used for comparison to determine if an object is in
motion,
- An object is in motion if the object changes position relative to a reference point.
- Reference direction is N, S, E, W, etc.
Distance
- Distance is the length of a path between two points.
Displacement
- Displacement is the length and direction an object has moved from its starting point.
Don't confuse distance with Displacement.
Speed
- An object's speed is the distance it travels in a given amount of time.
- Equation; Speed = distance/time
- S = d/t
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1/10/11 Science Notes: CH. 9; Motion and Energy
Position and Motion
- An object's position is defined by a reference point and a reference direction.
-A reference point is something used for comparison to determine if an object is in
motion.
- An object is in motion if the object changes position relative to a reference point.
- Reference direction is N, S, E, W, ect.
Distance
- Distance is the length of a path between two points.
Displacement
- Displacement is the length and direction an object has moved from it;s starting point.
- Don't confuse distance and displacement!
Speed
- An objects speed is the distance it travels in a given amount of time.
- Equation; Speed = Distance / time.
- Or S= d/t
Average speed Equation
- In most real world situations, speed is not constant but changes, requiring several
calculations.
- Average speed = Total distance/ Total time.
-Average S= total d/ total t.
-S subscript a= D subscript t/ T subscript t.
- D sub t= 32km= 13km = 45km
-T sub t= 2hr = 1hr = 3hr
- S = 45km/ 3hr= 15km/hr.
From, Serena
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