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Wachoviak
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72
Science
8th Grade
06/02/2012

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Term
Why is a model used in science
Definition
Models are used to help us visualize and understand interactions between objects that are too small or too large to see normally.
Term
Whats the purpose of lab 8.2- a black box?
Definition
b 8.2 (which we did not perform) encouraged students to imagine the arrangement of objects inside a closed box only by experimenting with their effect on each other when moved. (Visualizing through experimentation)
Term
Whats the purpose of "Rings and Fasteners" ?
Definition
ubber rings and metal paper fasteners were used to represent individual atoms. We then experimented with the outcome of attaching ‘atoms’ to one another in set ratios (FsR or FsR2) to make ‘compounds’, and examined the relationship between the mass of our ‘atoms’ and that of our ‘compound’. (We also identified a complete reaction as one that used up either all of the Fs or all of the R atoms.)
Term
define synthesis and decomposition
Definition
synthesis-start with multiple atoms&molecules that combine together to form a single, more complex compound.
Decomposition-reactions start with a single, complex compound that is broken down into smaller, simpler components.
Term
Define constant proportions.
Definition
constant value of the ratio of two proportional quantities
Term
How did Lavoister distinguish b/w 2 elements?
Definition
istinguished between compounds and elements by determining whether the substance could be broken down (decomposed) into other substances through chemical reactions.
Term
explain all the subatomic particles
Definition
Protons-positive-middle
Neutrons-none-middl
electrons-outside-negative
Term
Define Valence electrons. Determine number of them in an atom
Definition
Term
State the organizing principles of the Modern Periodic Table of Elements
Definition
Term
Know the location of metal, non metals, metalloids/semiconductors on the periodic table.
Definition
-metals, located in the lower left side of the table.
-Metalloids are located along the ‘stairs’ (zig zag line) between the metals and metalloids.
-Nonmetals are located on the upper right side of the table.
Term
Know the major families in the periodic table
Definition
-Alkali Metals – they are very reactive because they have only 1 valence electron.
-Halogens – they are also very reactive because they have 7 valence electrons.
-Noble Gases because they do not react with other elements.
Term
define light year
Definition
The distance that light travels in one year; about 9.46
trillion kilometers
Term
How did the process of the astronomical unit develop?
Definition
• Distances in the solar system are often measured in terms of the distance from Earth to the sun (one AU or 150 million km)
• Typically used to measure the distance of planets from the sun
Term
List the arrangement and the relationship between the sun, Earth, moon and planets.
Definition
• Order of the planets from the sun: Mercury, Venus, Earth, Mars (inner planets), Jupiter, Saturn, Uranus, Neptune (outer planets); the planets orbit the sun
• The moon (a satellite) orbits the Earth
Term
Identify the factors that allow the Earth to be the only planet that supports life
Definition
Term
State the Law of Universal Gravitation and know the relationship between the masses of the objects, the distance between them, and the resultant gravitational force
Definition
• F = G (m1m2/d2)
• All matter is affected by gravity
• Gravitational force increases as mass increases
• Gravitational force decreases as distance increases
Term
List the following astronomical bodies from largest to smallest: (a) star, (b) planet, (c) universe, (d) solar system, (e) galaxy
Definition
Universe, galaxy, solar system, star, planet
Term
Show the difference b/w universe, Galaxy, and solar system
Definition
Universe: space and all the matter and energy in it
Galaxy: a large collection of stars, gas, and dust that is held together by gravity
Solar system: the collection of large and small bodies that orbit our central star, the sun
Term
Describe the characteristics of a star.
Definition
-he color of a star tells about the composition (what
elements) and temperature
• Give off heat, light, and EM waves (no sound in space)
• Driven by nuclear fusion reactions (hydrogen and helium gas)
• Held together by gravity
Term
List the factors that contribute to the brightness of a star
Definition
• Apparent magnitude: how bright a star appears to be from Earth
• Absolute magnitude: how bright a star actually is
• Brightness is based on size and distance
Term
Identify what a constellation is and what determines when it is visible to us
Definition
• A group of stars which create a picture in the sky
• Constellations do not move; we see them in different locations due to Earth’s revolution around the sun
Term
Determine what elements are contained in a substance by analyzing results from a flame test or spectral analysis (IPS 8.7).
Definition
•Same color = same element
•First element of the compound produces the color (ex. Strontium chloride = red due to strontium)
Term
What is the result of combing all colors of the visible spectrum?
Definition
• The color you see is the color being reflected
• If you combine all the colors of the spectrum, you get white light
Term
What is the function of the spectroscope?
Definition
• Produces a spectrum of light for a particular element or compound
Term
How are the compositions of the inner planets and outer planets different?
Definition
• Inner: small, dense, rocky planets that orbit closest to the sun; terrestrial planets; consist of outer crust, central core, and a mantle
• Outer: gas giants; orbit farther from the sun; massive gas atmospheres, made up of mainly hydrogen and helium; no true surface for which to stand on
Term
Compare and contrast geocentric and heliocentric
Definition
• Geocentric: Earth-centered model of the solar system (Ptolemy)
• Heliocentric: Sun-centered model of the solar system (Copernicus, Kepler, Galileo)
Term
Differentiate between fission, fusion, and their applications.
Definition
• Fission: nucleus SPLITS into two or more smaller fragments; used in nuclear reactors
• Fusion: nuclei COMBINE (sun’s energy)
Term
Differentiate between a rotation and a revolution, and apply to the Earth and moon.
Definition
• Rotation: spinning on an axis
• Revolution: Circling around a larger body
Term
Compare and contrast a solar eclipse and a lunar eclipse.
Definition
• Solar: Earth, Moon, Sun (New Moon phase)
• Lunar: Moon, Earth, Sun (Full Moon phase)
Term
Explain how the phases of the moon occur and recognize these in the correct order.
Definition
The sun illuminates the moon; as the moon revolves around the Earth, we can only see certain parts
• New moon, waxing crescent, 1st quarter, waxing gibbous, full moon, waning gibbous, 3rd quarter, waning crescent
Term
Describe what effects the moon has on the Earth.
Definition
The moon’s gravitational force produces the water tides on Earth
Term
How does the increase in thermal energy of the cylinder relate to the mass of a falling object
Definition
As the weight fell, friction caused the cylinder to change temperature. This confirmed that gPE was converted into Thermal Energy (Heat).
Term
How do you determine the net mass in lab 13.1? How is it different from mass?
Definition
The net mass of the falling object could be found by taking the mass of the weight and subtracting the mass of the counterweight.
Term
Why must the distance the object falls be kept constant when testing the effect of mass on thermal energy of a falling object
Definition
Changing the distance of the fall would introduce a second variable.
Term
How is increase in thermal energy of a cylinder related to the verticle falling distance
Definition
Length of falling distance is proportional to ThE produced.
Term
State the law of universal Gravitation and know the relationship b/w masses of objects and the distance b/w them
Definition
-The Law of Universal Gravitation relates to the pull of gravity between two objects. (generally very large objects)
Term
What is the formula for GPE?
Definition
gPE = m g h
g=9.8
Term
differentiate b/w kinetic & potential energy
Definition
kinetic energy=energy of motion
potential energy=energy of position
Term
What factors influence kinetic energy?
Definition
speed & mass
Term
Whats the formula for kinetic energy?
Definition
KE=1/2mvsquared
Term
Can 2 people be moving at different speeds and have same kinetic energy? explain.
Definition
Two objects (people or otherwise) can have equal KE even if their speeds are different, if their masses are also different:
Term
When energy is transformed from one form to another what happens to the amount of energy?
Definition
In an ideal environment ( zero friction), all energy is conserved when it is transformed from one form to another.
Term
Definition
◦ A push or pull on an object
◦ Measured in Newtons (N)
Term
What changes with elevation – mass or weight?
Definition
◦ Weight changes, mass does not
Term
Differentiate between mass and weight. What tool is used to measure each?
Definition
◦ Mass is the amount of matter in an object; measured in kilograms; measured with a balance
◦ Weight is the pull of the earth (gravity) on an object; measured in Newtons; measured by a spring scale
Term
What is the relationship between mass and weight? How is weight calculated?
Definition
Term
How is elastic force different than gravitational force?
Definition
◦ Elastic force is the force exerted by the spring
◦ Gravitational force is the pull of the earth (gravity) on the object
Term
What is the relationship between magnetic force and distance?
Definition
Inverse relationship; as one goes up the other goes down
Term
What factors affect the frictional force between objects?
Definition
Term
How does weight and surface area affect the frictional forces?
Definition
◦ Weight is proportional to force of friction ◦ Surface area has no effect!
Term
Suppose that you kick a soccer ball. Which experiences a greater force 13 the ball or your foot?
Explain.
Definition
Your foot because the effect of the force you apply to the ball is greater than the force the ball applies back to your foot. The ball is originally at rest.
Term
Explain Newton 19s Third Law of Motion and give several examples.
Definition
-All forces acting between two objects along the line that connects them are equal in strength and opposite in direction.
-The spaceshuttle thrusters push the exhaust gases downward as the gases push the shuttle forward with equal force.
Term
Differentiate between balanced and unbalanced forces.
Definition
%E6 Balanced forces: equal in size and opposite in direction; do not cause a change of motion; net force equals 0 N
%E6 Unbalanced forces: not equal and opposite; net force does not equal 0 N; always cause a change in motion
Term
Define a vector and give examples.
Definition
%E6 Vectors are represented by an arrow.
%E6 Show the size (magnitude) and direction of a force
Term
what is the connection between the length/direction of a vector and the force?
Definition
%E6 Length represents the strength of the force
%E6 Direction indicates the direction of the force
Term
What is net force and how is it calculated?
Definition
Term
What do we call two forces that add to form a single force?
Definition
Components of the force
Term
What does the motion of an object look like after the forces acting on it end (Lab 15.6)?
Definition
When the push ends, the net force is zero, but the motion of the puck will continue to move in a straight line with a constant speed
Term
What are the two conclusions that make up Newton 19s First Law of Motion?
Definition
%E6 When the net force on an object at rest is zero, the object will remain at rest
%E6 When net force on a moving object is zero, the object will continue to move in a straight line at a constant speed
Term
What would constitute a violation of Newton 19s First Law of Motion?
Definition
%E6 Friction; opposes the force of motion and slows objects down
Term
Explain Newton 19s Second Law of Motion in your own words and provide several examples of the Law.
Definition
%E6 An object will accelerate in the direction of the force which is applied. The greater the mass, the more force is needed to accelerate the object.
%E6 Example: an empty shopping cart vs. a full shopping cart; the more mass, the more force is needed to accelerate the shopping cart
Term
how do you find force?
Definition
FxT=Mxchange in velocity
Term
what do plateaus indicate?
Definition
boiling point, a characteristic property
that can be used to identify an unknown substance.
Term
explain seperation by flotation
Definition
Term
What does the term "filtrate" refer to?
Definition
The solution of water and dissolved substance
Term
what must be order to separate a mixture of solids using the filtration method
Definition
the two solids must vary in solubility.
Term
what must be order to separate a mixture of solids using the filtration method
Definition
the two solids must vary in solubility.
Term
what must be order to separate a mixture of solids using the filtration method
Definition
the two solids must vary in solubility.
Term
explain the process of fractional crystallization
Definition
two solids which both dissolve in water are separated in a process which involves heating the water to dissolve one solid completely. Undissolved solid is then filtered out. Then the solution is cooled to filter out the previously dissolved solid.
Term
what technique can be used when seperating a mixture that contains only a minute amount of a substance
Definition
paper chromatography.
Term
how To remove CO2 that is dissolved in water?
Definition
heat water
Term
compare pure and substances and mixtures
Definition
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