UNDERSTANDING THE NATURE OF MATTER
Historically, much of the evidence and reasoning used in developing atomic/molecular theory was
complicated and abstract. In traditional curricula too, very difficult ideas have been offered to
children before most of them had any chance of understanding.
The atomic theory of matter suggests that:
By the end of the 8th grade, students should have sufficient grasp of the general idea that a wide
variety of phenomena can be explained by alternative
arrangements of vast numbers of invisibly
tiny, moving parts.
All matter consists of atoms.
All atoms of an element are identical.
Different elements have different atoms with a different number of protons, neutrons and
The center of the atom
contains the nucleus that has most of the mass of the atom. Holy Cow
batman it takes 2000 electrons to make one proton or neutron.
The charge of the atom is neutral because the number of protons in the nucleus equals the
number of electrons in the space o
utside the nucleus.
Electrons orbit the nucleus. When an electron moves from an outer orbit to an inner orbit, it
gives off energy (including light). When an electron moves from an inner orbit to an outer orbit,
it absorbs energy.
The packets of energy el
ectrons absorb or give off are called photons.
The atomic number is the number or protons.
A stable electron arrangement is an atom that has all the electrons at the lowest energy (orbital)
The atomic mass is the number of protons and neutrons.
e atomic mass is an average since the number of neutrons can vary in the atoms of one
Distinguish among the types of matter (e.g. elements, compounds, mixtures).
An element is a substance that
be broken down into other substances.
need to know there are 100 elements on the periodic table.
An atom is the smallest particle of an element that retains its properties of that
A compound is made of two or more elements that have been chemically
combined by s
haring electrons. They are combined in definite proportions. 2 hydrogen and 1
20 or water.
This is hydronium not Hydrogen. Notice the three
hydrogen atoms are sharing electrons with one oxygen atom. There are 4 atoms
and the formula is H30.
This is the Lewis structure or electron dot diagram for the hydronium ion.
A chemical bond is the force of attraction that holds atoms together by
LAW OF DEFINITE PROPORTIONS
that elements in a compound always combine in the
same proportion to make the molecules that make up the compound.
he smallest part of a compound is a molecule which is elements combined in a
definite proportion or set ration.
that reactant + reactant
product, is a shorthand way of showing the
elements of a molecule of a compound.
2 hydrogen + 1 oxygen
H20 or water. NOTICE
THERE ARE 3 atoms in
2 H and 1 O.
For our purposes
Elements are made of atoms, Compounds are made of molecules. Both are
COMPOUNDS AND MIXTURES ARE SIMILAR IN THAT THEY ARE MADE UP
Compounds (pure substance)
Mixture (not a pure substance)
Made of one kind of particle (H20
molecule, NaCl molecule,
Formed during a chemical change.
Broken down only by chemical changes.
Properties are different from its
Hydrogen and Oxygen are gases that burn.
H20 is a liquid that does not burn. Na
(Cl) are poisons but
you can eat table salt (NaCl).
There is a set formula and a specific
amount of each ingredient in the
molecules making the co
Made up of two or more molecules and
the amount can vary.
Not formed by chemical change.
Can be separated by physical changes.
Properties are the same as its parts. Sugar
water is sugar and water. The amount of
each can vary.
Does not have a defini
te amount of each
I can’t see the different
Students should become familiar with
characteristics of different states of matter
and transitions between them. Most important, students should see a great many examples
of reactions between substances that produce new substances very different from the reactants.
ey can begin to absorb the rudiments of atomic/molecular theory, being helped to see that
the value of the notion of atoms lies in the explanations it provides for a wide variety of behavior of
A physical property is one that ca
n be observed without changing the identity of
a substance. You can describe color, mass, shape, and volume.
Chemical properties describe the ability of a substance to be changed into new
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The idea of gravity
up until now seen as something
happening near the earth's surface
generalized to all matter everywhere in the
universe. Some demonstration, in the
on film or videotape, of the gravitational force
between objects may be essential to break through
the intuitive notion that things just naturally fall.
Weight is the measure of a planet’s pull of
If I take my
science book to the
moon, the mass stays the same but the weight
changes and is less than on earth.
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A change in color (A rotting
banana, a burning chair).
PH (acids 0 and bases 14,
remember 7 is neutral)
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Changes in state
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PERIODIC TABLE OF ELEMENTS
The elements in the Periodic Table are arranged in numerical order (1, 2, 3... 100) by the number of
This is known as the atomic num
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When I write a horizontal sentence, I end it with a period.
There are 7 periods.
FAMILIES or GROUPS
We are family, we go vertically. ELEMENTS IN A FAMILY OR GROUP HAVE
SIMILAR PROPERTIES AND ACT THE SAME AS OTHER ELEMENTS IN A FAMILY.
METALLOID DANCE Non
metals include non
metals, metalloids, and
Shiny, hard, conduct
active or reactive,
There is only one metal
that is not a solid
Have properties that
are in between metals
like the element Silicon
All solids that look
white and gray but are
not shiny. They will
conduct heat and
electricity but not as
well as metals and not
at all temperatures.
Each metalloid must
be studied individual
and all have some
properties of metals
and some of nonmetals.
Dull, brittle, good
insulators and poor
conductors of heat and
electricity, acidic, s
gases, some solids.
There is only one non
metal that is a liquid
Are all gases at room
temperature. They do
not react chemically
with other elements.
They are inert
UNDERSTANDING CHANGES IN MATTER
analyzing physical, chemical, and nuclear changes in
matter and the factors that affect these changes.
is a change that does not produce a new substance.
Chemical change (or chemical reaction( is any change of a substance (reacta
nt) into one or more other
PHASES OF MATTER
most common state of matter one earth.
shape, definite volume, low energy level
(cold), strong gravity attraction.
Indefinite shape, definite volume
(can’t make it
Indefinite shape (takes the shape of entire
container), indefinite volume, high energy level
(hot), week gravity attraction.
most common state of matter in universe
found in stars and lightning.
Is a gas that has bec
ome so hot that electrons have
escaped leaving a positive nuclei (nucleus with no
Physical Phase Changes
PHASE CHANGES ARE PHYSICAL CHANGES
Solid to liquid
Liquid to solid
to gas that takes place inside the liquid and
on surface. Endothermic
Liquid to gas over time. Takes place only on the
surface of the liquid. Endothermic
Gas to liquid. Exothermic.
no liquid state
Gas to solid
no liquid state
Solid to gas. Snow disappearing from a mountain
top where the temperature is below freezing.
Energy is released (exothermic) or absorbed (endothermic) in a chemical reaction.
Law of Conservation of Mass
Matter is neither created nor destroyed, just transformed. So chemical
equations must be balanced. 2H2 + O2
2H2O. reactant + reactant
become product (plus or
. Total matter and total energy remains the same.
rays (y) are high energy electromagnetic waves. Protection from gamma rays requires lead or
drogen nuclei fuse or join together to make helium nuclei. Nuclear
suns energy is generated by nuclear fusion.
Nuclear fission is the splitting of a nucleus into smaller fragments by
bombardment with neutrons. Controlled fission is the source of energy in nuclear power plants.
Identifying the components and properties of solutions, including a
bases, and factors that affect solubility.
OLUTE, SOLVENT, SOLUTION
the homogeneous solution produced when a solute is dissolved in a solvent.
the liquid that dissolves a solute. WATER
the solid that is dissolved
in the solute. Sugar, water,
when no more solute can be dissolved or with a paper towel no more water can be
no solute is present.
A can dissolve a lot more sugar in boiling tea and make it super saturated with sugar.
ACIDS AND BASES
Think of a number line 0 to 14 with 7 being the middle or neutral number. 0 is the A or Acid. And at
the other end B is the base. 7 is the neut
ral number. The farther from 7 the more acid a substance as
you go to 0 and farther from 7 the more base of a substance as you reach 14.
Metals are bases. Non
metals are acids.
Water is a neutral and is at 7 on the PH scale.
Acids have a sour taste (vi
negar and lemon juice), Bases have a bitter taste and the stronger ones feel
slippery. Many household cleaning products are bases.
Water is formed and when an acid and a base combine chemically
and a salt is also formed.
ANALYZING FACTORS THAT AFF
HEMICAL REACTIONS (E.G. TEMPERATURE
Kinetic energy is the energy of motion. Kinetic molecular theory says particles in stuff (matter) are in
constant motion. The particles do not lose energy in collisions. Most reactions increase tempera
because more and more molecules have the kinetic energy to overcome the reactions activation energy.
energy required to loosen bonds in molecules to allow them to
become reactive. The energy you give a match when yo
u strike a match on the match box.
A catalyst is a material that increases the rate of a chemical reaction without being changed
Two ways to increase the rate of reaction
Increase the temperature
meaning more molecules
collide per second, and these collision
occur with more energy and reach the activation level sooner. Try to start a fire on a hot day
compared to a cold day.
Increase the surface area of the reaction.
We set twigs on fire and then the big log. We don’t
start with the big log. Sugar dissolves better in small particles.
IDENTIFYING CHARACTERISTICS OF A SYSTEM AT EQUILIBRIUM
The activation is the minimum energy needed to overcome the barrier to the formation of products.
Remember reactant + reactant (plus or minus) energy
product (plus or minus) energy.
the energy of the products is lower
the energy of th
the energy of the products is greater than the energy in the reactants.
*** Energy is not created. When you strike a match you give energy from the food you ate that is added
to the reaction.
UNDERSTAND PRINCIPLES AND CONCEPTS
RELATED TO ENERGY
At this level, students should be introduced to energy primarily through energy transformations.
Students should trace where energy comes from (and goes next) in examples that involve several
different forms of energy along the way: heat,
light, motion of objects, chemical, and elastically
distorted materials. To change something's speed, to bend or stretch things, to heat or cool them, to
push things together or tear them apart all require transfers (and some transformations) of energy.
Food, gasoline, and batteries obviously get used up. But the energy they contain does not disappear;
it is changed into other forms of energy.
Identify forms (e.g. mechanical, chemical) and types (e.g., potential, kinetic) of
energy and their characteris
Friction is not energy. Friction is a force.
Energy is the ability to do work or supply heat.
Work is heat and heat is work. Work is the transfer of energy to move
not a form
of energy but a
method of transferrin
FIRST LAW OF THE
Energy is neither created nor destroyed. Energy is merely
transformed or changed from one form to another.
SECOND LAW OF THERMODYNAMICS
Heat can’t pass from a colder to a hotter body. And no machine
is 100% efficient. Some heat is lost to the environment and some sound is lost.
TWO TYPES OF ENERGY
(Position, An object’s energy stored in matter due to position
relative to ot
Moving, the energy of a moving object). A football in the air has both
types of energy.
KE = ½(m times v times v) or ½ mas times velocity squared.
PE = m times g times h. mass of the object times the gravitational pull on the ob
ject times the height
of the object.
Potential energy is stored energy. Kinetic energy is energy of motion.
Mechanical energy is the total potential plus the total kinetic energy.
THE ELEPHANT WITH A “P” ON HIS SWEATER JUMPS OFF A CLIFF.
Electric (moving electrons)
Nuclear (energy in atoms nucleus)
Radiation or EM
Chemical (energy in chemical bonds)
(Thermal or heat)
Common Energy Transform
Different types of stoves are used to transform chemical energy of fuel (gas, coal, wood,
into heat. Heat can then make water into steam and turn turbines to make electricity.
Solar collectors can be used to transform solar energy into
Windmills make use of the kinetic energy of the air molecules, transforming it into mechanical
energy that turns turbines to make electrical energy.
Hydroelectric plants transform the kinetic energy of falling water into electrical energ
A flashlight converts chemical energy stored in batteries to light energy and heat. Most of the
energy is converted into heat, only a small amount is changed into light energy.
Demonstrating knowledge of energy transformation and transfers (e.g. , h
transfer, energy conversion) in a system.
A slightly more sophisticated proposition is the semi
quantitative one that whenever some energy
seems to show up in one place, some will be found to disappear from another. Eventually, the energy
become quantitative: If we can keep track of how much energy of each kind increases and
decreases, we find that whenever the energy in one place decreases, the energy in other places
increases by just the same amount.
The energy that is transferred into or
out of a system is heat transfer.
In a closed system, if one substance loses heat then another substance must gain heat.
Heat of fusion
is the amount of heat it takes to change from a solid to a liquid or the loss of
energy in going from a liquid to a so
The heat that is required to change a substance from one state to another.
Heat of vaporization
the amount of heat that it takes to change from a liquid to a gaseous
Convection is not so much an independent means of heat transf
er as it is an aid to transfer of heat
by conduction and radiation. Convection currents appear spontaneously when density differences
caused by heating (conduction and radiation) are acted on by a gravitational field.
How many substances
2 or more
Heat travels through
a heated solid or
between two heated
solids that are
Heat travels through
a fluid (air or liquid)
density. Warm fluids
have a larger volume
as molecules move
faster and farther
apart so they are less
Heat transfer as the
waves of traveling
photons. The sun
warms the earth by
energy. Photons ar
packets of energy.
Applying knowledge of the gas laws (e.g. Boyle’s law and Charles’s law).
The behavior of gases
such as their compressibility and their expansion with temperature
be investigated for qualitative explanation; but the mathematics o
f quantitative gas laws is likely to
be more confusing than helpful to most students.
PRESSURE is the force exerted on each unit of area of a surface.
ressure is measured in a unit called
Temperature, Pressure, and Volume are related.
If Pressure goes up
Volume goes down.
Think of a squeezed
Then volume goes up.
Think of the balloon
Amber in a hot car.
If temperature goes
tire on a hot day
or a steel pressure
Then Pressure goes
up because volume
does not change.
Thermometers are an example of a one object with a constant volume (thermometer) and one
with a changing volume (alcohol or mercury inside).
When the temperature goes up, the liquid
expands inside because the volume does change.
Analyzing phase diagrams (e.g., heat versus temperature) and the flow of
energy during changes in states of matter.
The horizontal line where a solid object melts and a
liquid object freezes is important. On the
horizontal line, energy is being added (melting) or lost (freezing) BUT THE TEMPERATURE
REMAINS THE SAME because the energy is being used to overcome the intermolecular forces.
Heat capacity of an object is the
amount of heat energy that it takes to raise the temperature of
the object by one degree.
UNDERSTANDING ELECTRICITY AND MAGNETISM
Identify the characteristics of static electricity and explaining how it is
A plastic rod that is rubbed with fur
or similar object will become electrically charged and will attract
small pieces of paper. The plastic rod gathers electrons while the fur loses electrons.
This is a change
creating positive and negatively charged objects.
A neutral obj
ect has no net change. The plastic rod and fur are initially neutral.
Materials through which electric charges can easily flow. Think metals.
A material through which electric charges do not flow easily, it at all. Think non
Charges can be removed from an object by connecting it to earth through a conductor.
The removal of electricity by conduction is called grounding.
Electrically charged objects share these characteristics.
Like charges repel one another.
Opposite charges attract each other.
Charge is conserved.
Applying knowledge of the flow of electrons in circuits including the
relationships between voltage,
An electric circuit is a path along which electrons flow.
The light, ringing bell, television, in a circuit is an example of a load. A load is any device that
The energy behind the moving electrons in a circuit. Think of
a water faucet. The more I cut
it on the more voltage.
The number of electrons per second that flow past a given point. Think of water leaving the
water hose after going through the water hose.
The ability of the material to oppose
the flow of electrons through. Think of the friction of
the water hose one the water as the water goes through it. The longer the wire the more the
resistance. The thinner the wire the more the resistance. Think of a long water hose (high resistance)
nd think a thick wide water hose has less resistance compared to a thin narrow hose. Compare a
garden hose to a hose on a fire truck.
A switch is a device that opens or closes on a circuit. If you press a buzzer and it rings, the
buzzer is acting
as a switch.
Comparing and Contrasting series and parallel circuits and how they transfer
How many paths for the
One or more.
If one light goes out.
All the lights go out.
The other lights stay
If I add a light
The rest get dimmer because
The brightness stays the same.
Since there are other paths the
resistance stays the same.
Recognizing the characteristics and uses of magnetic domains, magnets, and
Two ways to get rid of a magnet
hit it really hard making the electrons and their fields random. Or
making the object really hot giving the electrons enough energy to become random.
The space around a magnet where its force will act on o
is the result of electrons in motion.
When electrons all spin in the same direction and set up magnetic fields going in
the same direction inside the metal object.
You can make a magnet out of an iron nail by repeatedly
stroking the nail in the same direction with
The magnets on your refrigerator. If you break the magnet in half, each piece will still be
Magnets have a north and south pole. Opposite sides attract and the same sides r
Nickel, Iron, and Co
three elements that are metals and easily become magnets or electro
Demonstrating knowledge of the relationship between electricity and
magnetism and applications of electromagnetism and electromagnetic
uction (e.g., motors, generators, transformers).
A magnet can be made out of a coil of wire by connecting the ends of the coil to a
battery. When the current goes through the wire, the wire acts in the same way that a magnet does.
called an electromagnet.
An electromagnet can be made more powerful in four ways.
Make more coils.
Move the coils closer together.
Put an iron core (nail) inside the coils.
Use a stronger battery source.
Magnets and Electricity
When the battery is disco
nnected, the compass
would point north. Notice the compass changes when the positive and
negative are reversed on the battery.
hese special properties of magnets can be used to make electricity. Moving
magnetic fields can pull and push electrons. Some
metals, like copper
have electrons that are loosely held. They can be pushed from their shells
by moving magnets. Magnets and wire are used together in electric
that turns rotary mechanical energy into electrical energy
Turbines are rotary engines that extract energy from moving fluids like air or water.
Turbines are attached to electrical generators which actually convert the mechanical energy in the
turbine into electricity.
An electrical dev
ice that either increases or decreases the electricity voltage.
Step up transformer
Electricity comes in on a few coils and leaves on a lot of coils. Increasing voltage.
Step down transformer
Electricity comes in on a lot of coils and leaves on only
a few coils. Decreasing
IDENTIFYINYING THE PROCESSES INVOLVED IN THE TRANSFORMATION OF
MECHANICAL ENERGY INTO ELECTRICAL ENERGY AND THEN THE TRANSMISSION
OF ELECTRICAL ENERGY.
Almost any form of energy can be transformed into another form.
Often it is mechanical energy that is
transformed into electrical energy. Examples:
Hot gases or steam: Heat produced by nuclear reactions or the combustion of fossil fuels can be used to
boil water or create steam. Alternatively solar water can be captu
red to heat the water.
Water: As is seen in hydroelectric dams, the natural flow of water can be used to drive a turbine.
Wind: Naturally occurring wind can be collected using windmills, which directly link to the turbine.
UNDERSTAND THE PROPERTIES OF WA
VES, SOUND AND LIGHT.
Comparing and contrasting characteristics of longitudinal waves and transverse
Wave length should be the property receiving the most attention but only minimal calculation.
the initial event or vibration that star
ts the wave.
a rhythmic disturbance which travels through space (EM waves) and matter.
There are two types of waves.
T T T Transverse waves
the particles in the waves move perpendicular to the movement of energy.
The waves go up and down and the energy goes across.
L o o o o ngitudinal waves or compressional waves
the particles in the waves move parallel to the
movement of energy.
crest, trough, rest position, amplitude (going up or going down),
wave length, nothing
rarefraction, compression, wavelength.
FOR OUR PURPOSES
Light waves are the example used for transverse waves and sound waves are
the example used for longitudinal or compression waves.
Parts of a Transverse wave
crest, trough, rest position, amplitude, wave length.
Parts of a Longitudinal
compression, rarefaction, and wave length.
The number of waves that pass a given point in one second. Think of a runners on a track
crossing a line.
Long waves have a low frequency and short waves have a high frequency.
SPEED of wave
SPEED (V) = (wavelength)(frequency).
Analyzing how the behavior of waves is affected by the medium (e.g., air, water
solids) through which the waves are passing.
The bending of waves as they enter a new medium. As EM waves enter the atmosph
or waves enter water, the speed of the part in the new medium decreases.
Waves that bounce of an object.
Sound waves need a medium in which to spread. Light waves are EM (electromagnetic) waves and do
not need a medium.
Sound travels fa
stest in solids. Slows down in a liquid. And is the slowest in air.
Light travels th
e fastest in
in air, slower in a liquid and slowest in a transparent solid.
when the wave is absorbed by an object. Heat is absorbed by black objects.
When I see white all the colors are being reflected. When I see black, no light waves are being reflected
to my eyes. When I see a red shirt, red light waves are being reflected
to my eyes.
Analyzing the phenomena of
, refraction, interference, diffraction,
polarization, dispersion, and absorption.
When light hits a surface, it is reflected. The angle of incoming light is the ANGLE OF
INCIDENCE) and the li
ght leaves at the same angle called the ANGLE OF REFLETION. You see objects
when the reflected light hits your eyes.
When light hits a rough surface, the light is scattered in many different
When light enters
a second or new medium and bends.
is the change in direction of a
due to a change in its
This is caused by light ente
ring a new medium
Going from air to water.
Note: Refraction does not stay in the same medium.
diffraction stays in the
change medium. Diffraction, same medium
refraction of light going through a different medium.
Notice in the first diagram
that when light leaves, it is at the same angle as when it entered the solid.
When light stays in the same medium but bends around a barrier. Or light comes under
When two waves meet and cross paths in the same medium.
When two crests meet and the amplitude becomes much larger. This
can also happen with two troughs meeting and there is a much larger amplitude. Energy
When a crest of one wave meets a trough of another wave creating a
amplitude or even the rest position. Energy is
2 waves, node, antinode, wavelength. Below is a noise cancelling
headphone. Notice you hear nothing since the amplitude is zero.
Like water being picked up by a paper towel, energy from a wave can be absorbed. Black
clothes absorb energy and white clothes reflect energy.
hits the object and is most of the light is
transmitted out the other side.
Details are clear
Light hits the object and some light is transmitted
out the other side but the details are no longer
clearly visible. Like looki
ng through a curtain.
Light is reflected or absorbed but does not go
the object. No details are visible.
Demonstrate knowledge of characteristics and uses of electromagnetic
Slow and Cold E
LECTROMAGNETIC SPECTRUM hot, high frequency
Turn on a
this side of
How is a mechanical sound wave (longitudingal) transmitted between astronauts?
It is not
transmitted. It is converted into a transverse EM sound wave which can travel in outer space and then
converted back to a mechanical sound wave inside the astronauts
are thinner in the middle and thicker or the top and bottom.
Convex mirrors and lens
are thicker in the middle and thinner on the top and bottom. Think of a santa
Concave mirrors and convex
lenses can produce real images.
use the internal reflection of light and are used to carry telephone messages and are
used to carry light inside our body to see inside our throats etc.
Demonstrate knowledge of the properties of sound
and light in everyday
phenomena (e.g. echoes, Doppler effect, magnification, and rainbows).
Sound (this is not a EM radio wave!)
Light (this is an EM wave)
T T T Transverse wave
pty it does not need a
Produced by a vibrating medium (solid liquid or
Produced by vibrating electrons that send out
photons which are packets of energy.
Travels fastest in a solid then liquid then gas and
cannot travel in outer space. It ca
n’t travel in space
because there are no particles to vibrate.
All waves travel the fastest and at the same speed
in empty outer space. They slow down and
separate in solids, liquids and gases.
are sound waves being reflected by a mediumand retur
ned to your ear. .
are light waves being refracted.
Refraction and Reflection in
since water is more dense
than air, light is refracted as
it enters the drop
bent less, blue more some of
the light will reflect off the
back of the
drop if the angle
is larger than the critical
angle (48° for water) the
light is then refracted again
as it leaves the drop, the
colors of white light have
will leave the drop
at an angle of 40° from the
beam of sunlight
will leave the drop
at an angle of 42° from the
beam of sunlight
this process generates the
Notice you can’t see two colors from one drop because the
wavelength of the other colors don’t come to your eye.
Only one wavelength per drop.
However, you can not see
the blue light and red light
refracted from the same
So, many drops are involved
in producing the r
The amplitude of a sound wave determines the loudness. Large amplitudes are loud and
have a large intensity of energy.
The intensity of a sound wave is the amount of energy in a wave it is similar to loudness but
if you think about it, loudnes
s is subjective.
The pitch of sound is based on how many waves are going by. High frequency means high
pitch. Slow means low.
A duck swimming sends out round waves of energy. As the duck moves forward so the
circles in front a
re squeezed together (high frequency and pitch). The waves behind spread out as the
duck moves away (slow frequency and low pitch). THINK OF RACE CARS.
Doppler shift with light
. An object sending out light moving toward you shifts to
(shorter wave l
ength) and the light shifts to red when the object is moving
away (longer wave length).
The color of the shirt is the color being reflected to my eye the other colors are being absorbed.
Sound waves that do not happen with regularity and which are unpleasant are called noise.
Think of static.
Demonstrating knowledge of the relationship between properties of waves and
how they are perceived by humans (e.g., color, pitch)
When we refer
to light, we are usually talking about a type of electromagnetic
wave that stimulates the retina of the eye, or visible light.
Each individual wavelength within the spectrum of visible light represents
when all the colo
rs are reflected to my eyes I see white.
when all the colors are being absorbed and no light waves are reaching
my eyes, I see black.
When we see red, all the colors are being absorbed except red which is
When we see black, it is because all the colors are being absorbed and
no colors are being reflected.
Sound waves that do not happen with regularity and which are unpleasant are called noise.
Think of static.
Primary colors of light
Primary colors of pigments
yellow, cyan, magenta.
Comparison of Additive and Subtractive Primay Colors
Secondary colors of one system serve as the primary colors for the other.
red slower frequency
So the hottest fires are
blue/violet in color and
the new cooler lightbulbs
put out more of a red
violet and blue are
faster and hotter.
UNDERSTAND THE RELATIONSHIPS AMOUNG FORCE, MASS, AND THE
MOTION OF OBJECTS.
force/motion relationship can be developed more fully now and the difficult idea of inertia be
given attention. Students have no trouble believing that an object at rest stays that way unless acted
on by a force; they see it every day. The difficult notio
n is that an object in motion will continue to
move unabated unless acted on by a force. Telling students to disregard their eyes will not do the
the things around them do appear to slow down of their own accord unless constantly pushed
or pulled. Th
e more experiences the students can have in seeing the effect of reducing friction, the
easier it may be to get them to imagine the friction
COMPARING TYPES AND CHARACTERISTICS OF FORCES (e.g. frictional and
gravitational) and analyzing
the effects of forces on objects.
is the study of the relationship between motion and the forces affecting motion.
Force causes motion.
Heat is work and work is heat.
If I go to the moon, the mass of my science book stays the same but
the weight changes.
Mass is the amount of matter in an object.
Weight is the measure of the pull of gravity of a
planet or moon on an object.
Mass stays the same
Mass is also a measure of an objects resistance to
acceleration (going faster, stoping or changing
Every object in motion has a property called momentum. Momentum = mass times
The greater the momentum of an object, the more force it takes to stop it. Harder to stop
a train at 10
miles per hour then it is to stop a first grader at 10 miles an hour.
depends on 1) the type of surfaces touching and 2) how hard the surfaces are touching.
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Analyzing the relationship between the displacement, velocity, and acceleration
of an object graphically, algebraically, and in w
To have movement, there must be a change in distance between two objects.
is how fast and object is traveling. Speed = distance / time.
gives me the direction as well as the speed. How fast and object is traveling and in
direction it is traveling.
speed at a given instant.
When an object moves in a circle, the centripetal force is the force that directs the
object toward the center of the circle and keeps it the object from g
oing in a straight line. The earth’s
gravity is the centripetal force that keeps a satellite and the moon going in a circle.
The average of all instantaneous speeds. Total distance / Total time.
Is the rate at which an ob
ject changes velocity. Said another way it is the change in
speed (faster or slower) or the change in direction (going in a circle).
Acceleration = (final velocity
starting velocity) /time.
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Newton’s laws of motion and applying them to everyday situations.
Newton’s Three Laws of Motion
The law of inertia
Objects at rest will remain at rest until acted on
by an external force and
objects in motion will remain at motion traveling at a constant velocity (at same speed in a
straight line) until acted upon by an external force. On earth, friction is an external force that
slows objects down.
Force = mass times
acceleration. Memorize the formula. If a net force acts on an object, it will
cause the acceleration of an object (go faster, slower, stop, change direction).
For every action, there is an equal but opposite reaction. When I kick a soccer ball, I exert
equal but opposite force on the ball and the ball exerts a force on your foot. Don’t believe me,
try kicking a wall.
PUSH AND PULL
Pushing a table or pulling a bowstring applies a muscular force when the muscles
expand and contract. This is an ela
stic force when any object returns to its original shape (your muscles
or the bow string).
for every action there is an equal but opposite reaction. When he pulls, an unbalanced
force is applied from wheels to ground and ground to wheels. So they
don’t cancel. No
not move. No. Must move to do work.
Friction opposes (goes in the opposite direction) the motion of one surface going past
another. The air hitting your face on a bicycle or the friction of the ground on a tire.
ULL OF GRAVITY
Any two objects, any two molecules, any two atoms have a force of attraction
between them called gravity. Basically, positive electrons of one object are attracted to negative
electrons of another object and vice a versa.
All masses are
attracted to other masses (gravity)
Gravity is changed by mass.
More Mass/Gravity Less Mass/Gravity
If the mass of one or both of the objects is
then the gravity between them is also
Gravity is changed by distance
If the distance between the objects is
the gravity between them is
The amount of gravity between two objects is called weight.
FORCES ON AN OBJECT AT REST
When all the forces on an object are balanced, the law of
that the object does not move and continues to remain at rest. A boat wants to float down the river
because of the force of the water but the force of the rope holding the boat to the dock is greater and
the boat does not move.
FORCS ON A MOV
When forces are balanced, the law of inertia says that the object
continues traveling at the same speed and in the same direction.
INERTIA AND CIRCULAR MOTION
The high banking of a curved race tack and the f
riction between the
wheels and the road keep an object moving in a circle called centripetal force.
Which has more momentum a 3600 kilogram truck moving at 8 kilometers per hour or an 1800 kilogram
truck moving at 16 kilometers per hour.
ntum (force) = mass times acceleration (speed).
Truck = 3600 kg x 8 km/hr = 28800 kg/km/hr
Car = 1800 kg x 16 km/hr =28800 kg/km/hr.
What if the truck and car are moving at the same speed of 8 kilometers per hour
The car has ½ the momentum. Car
= 1800 kg x 8 km/hr = 14400 kg/km/hr.
APPLYING KNOWLEDGE OF CONEPTS OF WORK, POWER, EFFICIENCY, AND
The ability to do work.
The method of transferring energy from one object to another.
Work is done on an object when a force is applied and the object moves
some distance. IF the object does not move, no work is done.
Work = force times distance.
Power is the rate at which work is done or how fast work is done. Power =
t of work divided by time. Walking and running the same distance
do the same amount of work but running requires more power.
The law of conservation of energy says that energy cannot be created or
destroyed. It may be transformed from one for
m to another but the total
amount of energy never changes. Efficiency is the relationship between the
energy input and the energy output. A car loses some efficiency as energy is
transformed to heat and sound rather then making the car move.
y = useful energy produced times 100 divided by total energy used.
There are two types of mechanical advantage.
Ideal mechanical advantage
no energy is lost from friction, heat,
light, sound, etc.
Actual mechanical advantage
The mechanical advantage the is
found in the real world where some energy is converted into wasteful
forms that are not useful.
Remember if distance goes up, force goes down but total work is always
the SAME. Think of a ramp compared to stairs.
ork to make money to buy my lovely wife some
Ask me what power is measured in?
I use force to open up my bag of fig
and eat them.
So work is measured in joules, power is measured in watt, and force is measured in neutons.
on is measured in
Sound is measured in
because it hurts my ears.
IDENTIFYING TYPES AND CHARACTERISTICS OF SIMPLE MACHINES.
6 types of Simple Machines
Wheel and axle
Changes direction of the force.
two inclined planes
the wedge moves doing the work over a greater distance so
an inclined plane wrapped around.
Compound machines are two or more simple machines working together. A wheelbarrow is a
lever and a wheel and axle worki
Increase efficiency by decreasing friction.
3 types of levers
First class lever
= The fulcrum is between the
effort force and resistance force.
See saw, scissors, pulling a nail with a hammer.
Second class lever = The resistance force is
between the effort force and the fulcrum.
Wheel barrow, pecan cracker, or a bottle opener.
Third class lever = The effort force is between the
resistance force and the fulcrum.
Raking leaves, hitting a b
aseball, using a fishing
First class lever
Second class lever
Third Class lever
What it does
The Lever Family
A stiff structure that pivots on a
support called a fulcrum
Lifts or moves loads
wheel with a rope or
cable around it
Moves things up, down, or
A wheel that turns about an axle
through its center; both wheel and
axle move together
Lifts or moves l
Inclined Plane Family
A sloping surface connecting a
lower level to a higher level
Things move up or down it
An object with at least one
slanting side ending in a sharp
Cuts or spreads an object
Front of a boat
An inclined plane wrapped around
Holds things together or lifts