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S8P1 - The Structure of Matter Review
Matter is anything that has mass and takes up space. There are two types of pure substances: elements and
compounds.
Elements are substances that cannot be further broken down into simpler substances.
An atom is the smallest particle of an element.
A nucleus is the center of an atom.
A proton is a particle found in the nucleus of an atom that has a positive charge. Always the atomic number.
A neutron is a particle found in the nucleus of an atom that has no electrical charge.
An electron is a particle outside the nucleus of an atom that has negative charge.
An ion is an atom that carries a positive or negative charge because it either has gained or lost electrons.
Isotopes are atoms of an element with different numbers of neutrons in their nucleus. Ex. Cl-17, Cl-18, Cl-19
Compounds are formed when the atoms of two or more elements combine (chemically bond) to form a new substance.
A molecule is a particle that is made up of two or more atoms.
A chemical formula is a representation of a compound using its chemical symbols
A chemical bond is a connection between atoms
A mixture is formed when two or more elements combine (physically) but do not form a new substance.
Heterogeneous mixtures are mixtures of substances that are not distributes evenly throughout the mixture. Ex.
Trailmix, tossed salad, taco salad
Homogeneous mixtures are mixtures of substances that are evenly distributed throughout the mixture. Ex.
Kool-Aid, milk.
A solution is a special kind of homogenous mixture in which one substance (solute) is completely dissolved in
another substance (solvent). Ex. Saltwater = water(solvent) + salt (solute)
The periodic table of elements is a chart that organizes all the elements based on their atomic numbers and properties.
There are over 100 elements on the periodic table. Most of the elements on the periodic table are metals.
A chemical symbol is an abbreviation of the name of an element.
The atomic number is the number of protons in the nucleus of an atom.
The average atomic mass of an element is the average mass of the atom mostly from the nucleus.
Groups (Families) are the vertical columns in the periodic table. There are 18 groups. Elements in the same
group have similar chemical properties and react similarly to other elements.
Periods are the horizontal rows in the periodic table. There are 7 periods.
Metals are elements that are good conductors of electricity and heat, usually shiny, malleable, ductile and are
all are solids at room temperature except Mercury. They are located on the left side of the Periodic Table.
Nonmetals are elements that are poor conductors of electricity and heat. Most are gases at room temperature.
They are located on the right side of the Periodic Table.
Metalloids have properties of both metals and nonmetals. They are semiconductors, or partial conductors of
electricity. They are located along the zigzag line of the Periodic Table.
Group 1 – Alkali Metals (except hydrogen) - extremely reactive; one valence electron; commonly with Group 17
Group 2 – Alkaline Earth Metals- denser and slightly less reactive than Group 1; two valence electrons;
commonly with Group 16
Groups 3-12 – Transition Metals – denser and less reactive than Groups 1 or 2; varying valence electrons
Group 17 – Halogens – very reactive; nonmetals with seven valence electrons (gains electrons)
Group 18 – Noble Gases – eight valence electrons (except helium); most chemically stable; nonreactive (inert)
States of Matter – the physical form in which matter exists. There are four states of matter: solids, liquids, gases and
plasma.
Solids have a definite shape AND a definite volume. Particles are packed closely together; particles vibrate and move in
place and do not slip past one another. Slow speed particles.
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Liquids have a definite volume BUT NOT a definite shape. Particles are in contact with one another and move quickly
past one another. Medium speed particles.
Gases DO NOT have a definite shape NOR a definite volume. Particles are normally not in contact with one another.
Particles move quickly in straight lines and bounce off one another and the surface of the container they are in. Gases
take the shape and volume of the container that holds them. Fast speed particles.
Plasma DO NOT have a definite shape NOR a definite volume, but forms at very high temperatures (like stars)
Temperature and Changes of State
Particles move faster the higher the temperature. The energy of motion is called kinetic energy. Temperature is a
measure of the average kinetic energy of the particles in a substance. The faster the particles in a substance move, the
higher the temperature. The slower the particles move, the lower the temperature.
Matter can change from one state to another (physical change). A change in state requires that matter either absorb
energy (thermal energy or heat or gets hotter) or release energy (thermal energy or heat or loses heat).
When energy is added (gets hotter) the particles move faster. Solid to liquid (melting), liquid to gas (evaporating /
vaporization)
When energy if removed (gets cooler) the particles move slower. Gas to liquid (condensation), liquid to solid (freezing)




Melting Point - the temperature at which a substance melts.
Boiling Point – the temperature at which vaporization, or boiling occurs.
Freezing Point – the temperature at which a substance freezes.
The Melting Point and Freezing Point are the same temperature for a substance.
Properties
Physical Property – a characteristic that can be observed or measured without changing the identity of a substance.
Ex. color, hardness, magnetism, state, density, mass, weight, melting point, boiling point, freezing point, solubility,
conductivity.
Chemical Property – a characteristic that determines how a substance will interact with other substances during a
chemical reaction. A chemical property cannot be observes without changing the substance. Ex. combustibility,
reactivity, flammability, ability to rust, reaction to light, reaction with acids, etc.
Changes
Physical Change – a change that alters the physical properties of a substance without changing the identity of the
substance. Many physical changes can be reversed to change the matter into its former condition. Ex. cutting, melting,
freezing, boiling, mixtures being formed, etc.
Chemical Change – a change that occurs when one substance is changed into a new substance with different
properties. Some signs that a chemical change may have occurred include the formation of a precipitate, formation of
gases or a change in color and heat or light being given off. Ex. baking a cake, rusting, elements reacting, burning,
compounds being formed, combustion, etc.
Law of Conservation of Matter states that matter cannot be created or destroyed. It can only change from one form to
another. This means that the sum of the reactants = sum of the products.
Reactants – the substances that are present before the reaction occurs and are changed by the reaction.
Products – the substances present after the reaction takes place.
Reactants
Products
CH4 + 2O2  CO2 + H20
subscripts
coefficient
subscripts
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Subscript is a small number written to the right (behind) of the element. It indicates the number of atoms of that
element only in the molecule or compound.
A coefficient is a large number written to the left (in front) of the element or compound. It indicates the number of
atoms (elements) or molecules (compounds).
reactant side = product side
CH4 + 2O2  CO2 + H20
16grams + ?
 44 grams + 36 grams
16 grams + ?

80 grams
80grams – 16 grams = 64 grams which means ? = 64 grams
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S8P2 – Energy and Its Transformations Review
Energy is the ability to do work. Energy is measured in a unit called Joules (J). Work is a measure of force applied over a
distance to move an object. In order for work to be done, a force has to be applied and the object has to move in the
direction of the force. Work is also measured in Joules. Work can be calculated using the formula:
work = force x distance
There are two broad categories of energy: potential energy and kinetic energy.
Potential energy (PE) is the energy stored in an object because of its position or composition. It has the “potential” to do
work. It is measured in Joules. An object that is elevated higher has more potential energy than the same object at a
lower elevation. Items like fuel (gas or coal) have potential energy. Uneaten food has potential energy. Gravitational
potential energy (GPE) can be calculated using the formula:
GPE = mass (in kg) x gravity (in m/s2) x height (in m)
Remember gravity = 9.81m/s2
2 2
1 kgm /s = 1 Joule
Kinetic energy (KE) is the energy of motion. It is also measured in Joules. KE depends on two factors: the mass of an
object and how fast it is moving (speed). KE can be calculated using the formula:
KE = ½ mass (in kg) x velocity (in m/s)2
Law of Conservation of Energy states that energy cannot be created nor destroyed, but it can change from one form to
another.
Potential energy can change to kinetic energy and kinetic energy can change to potential energy. Ex. at the top of a
roller coaster’s first hill, it has its greatest potential energy. At the bottom of the first hill that potential energy has been
transformed to kinetic energy.
Ex. as a pendulum swings, the energy is transformed from PE to KE and back to PE. It has its greatest PE on the upswing
ends of the pendulum before it falls aback down. It has its greatest KE at the bottom of the swing before it starts its
upswing.
There are many different forms of energy that fall into the PE or KE categories.
Potential Energy: Stored Energy
Kinetic Energy: Energy of Motion
Chemical Energy: energy stored in the bonds that hold
Electrical Energy: energy of moving electric charges
atoms together (food, gas, batteries)
(lightning, charged particles in a circuit)
Nuclear Energy: energy stored in the nuclei of atoms;
Radiant Energy: energy that travels as electromagnetic
released when nuclei join together (fusion) or split apart
waves. (gamma, radio, x-ray, infrared, visible light,
(fission)
microwaves, ultraviolet)
Gravitational PE: energy of position (roller coaster,
Sound Energy: energy given off by vibrating objects;
pendulum)
energy we can hear (voices, music)
Stored Mechanical Energy: energy stored in an object
Mechanical Energy: energy of motion, used to do work
because a force was applied to it (stretched rubber band – (flowing water, windmills, your moving body)
elastic PE)
Thermal Energy: energy of the moving particles that make
up matter (geothermal energy, energy to maintain your
body’s temp.
All of these can change from one form to another.
Thermal Energy is the total kinetic energy of all particles in a substance. The thermal energy of a substance depends on
two factors: the temperature of the substance and how much substance there is. Temperature is a measure of the
average kinetic of all the particles in a substance.
When the motion is a substance changes, the temperature changes too. The faster the particles move, the higher the
temperature. The slower the particles move, the lower the temperature.
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Thermal energy and temperature are closely related, but they are not the same. Temperature is an average. It does not
depend on the amount of particles.
Heat is the flow of thermal energy. Heat always flows from an area of higher temperature to an area of lower
temperature. It will flow this way until all materials are the same temperature. It can be transferred in three ways:
conduction, convection and radiation.
Conduction is the transfer of heat by direct contact of particles (frying an egg). Convection is the transfer of heat in
fluids by the movement of currents that form in the fluids (boiling soup). Radiation is the transfer of heat without
matter (sun shining). Conduction and convection REQUIRE MATTER. Radiation does not.
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S8P3 – Force and Motion Review
Motion is a change in position over time. To make sense of motion, you can use a reference point. A reference point is
a stationary object such as a building, street or tree. Once you have a reference point, motion can be defined in terms of
position, direction and speed.
Position refers to an object’s location relative to a reference point. Direction is the line or path that an object moves
along. Displacement is the actual distance between the starting and ending points (in a straight line).
Speed is a measure of the distance traveled per unit of time (the rate at which an object is moving). To calculate speed,
you need the distance traveled and the time it takes to the travel the distance. Speed can be calculated using the
formula:
speed = distance / time
Speed is usually measured in the units meters/second, miles per hour or kilometers per hour.
Velocity is speed in a particular direction. It is measured in the same units as speed, but is also MUST HAVE a direction.
Distance (meters)
Distance-Time Graph
100
50
0
0
10
20
30
40
50
60
70
Time (seconds)
This graph show two objects moving at constant speed for the first 30 seconds. At 30 seconds, the dotted line stops
moving and is motionless for the next 30 seconds. The solid line moves at a constant rate for the entire 60 seconds.
Also, the steeper the line, the greater the speed. The dotted line is moving faster than the solid line for the first 30
seconds.
Acceleration is the rate of change in velocity, or the change in velocity per unit of time. Acceleration can occur in three
ways: speed up (positive acceleration), slow down (deceleration or negative acceleration) or changing direction.
Acceleration is measured in m/s/s or m/s2.
Distance-Time Graphs
Increasing velocity
Distance
(m)
Decreasing velocity
Constant velocity
Distance
(m)
Distance
(m)
Time (s)
Time (s)
Time (s)
Velocity-Time Graphs
Positive Acceleration
Velocity
(m/s)
Negative Acceleration
Velocity
(m/s)
Velocity
(m/s)
Time (s)
No Acceleration
Time (s)
Time (s)
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Force – a push or pull. Force is measured in Newtons (N).
Net Force – the sum of all the forces acting on an object. Balanced forces are forces that produce a net force that is
equal to zero. When forces are balanced, there is no change in motion. If it is a rest it continues at rest, If it is in motion,
it continues in motion moving at the same speed in the same direction. Unbalanced forces are forces that produce a net
force that is greater than zero. The object acted on moves in the direction of the greater force.
Inertia – the tendency of an object resist a change in its motion.
Newton’s Laws of Motion
1st Law of Motion – an object at rest tends to stay at rest. An object in motion tends to stay in motion and move at the
same speed in the same direction unless acted upon by an unbalanced force. ( law of inertia)
2nd Law of Motion – the force acting on an object is equal to the mass of the object multiplied by its acceleration.
(Force=mass x acceleration; acceleration depends on force and mass.)
3rd Law of Motion – for every action, there is an equal and opposite reaction. (Forces act in pairs. When two objects
interact, one force acts on the first object, and the other force acts on the second object.)
Friction- a contact force that acts between two surfaces that touch each other. It opposes motion. Friction is greater for
a heavy object than for a light object. There are three types of friction: static friction, sliding friction and rolling friction.
Static friction – associated with the resistance created when trying to move heavy objects and the particles between the
object and the floor have bonded (welded.) The more mass an object has, the greater the static friction.
Sliding friction – associated with an opposing force/resistance that slides past an object.
Rolling friction – associated with objects rolling.
Gravity – a noncontact force that attracts objects toward one another. According to Newton’s Law of Universal
Gravitation, all objects can attract all other objects in the Universe. The amount of gravitational attraction between
two objects depends on two factors: the distance between them and the masses of each. If the mass increases, gravity
increases. If the distance between the objects increases (farther apart), gravity decreases.
A simple machine is a device that makes work easier by changing the size, direction or both size and direction of the
force used to do the work. They DO NOT reduce work, they only make it easier. There are six simple machines: lever,
pulley, wedge, wheel & axle, inclined plane and screw.
Inclined Plane – a straight, slanted surface (ramp). It increases the distance that work is done, but decreases the force
needed.
Wedge – two inclined planes placed back to back. (knife). Wedges transfer force in one direction into force in two
directions.
Screw – a inclined plane that is wrapped around a cylinder. A screw applies a small force over the long distance of the
screw’s threads.
Lever – a simple machine made up of a bar that pivots (fulcrum) at a fixed point. The force applied to a lever is the
effort. The object moved is the load. They are classified three ways: 1st class, 2nd class and 3rd class.
 1st Class – the fulcrum is between the effort and the load. Ex. seesaw
 2nd Class – the load is between the fulcrum and the effort. Ex. nutcracker or wheelbarrow
 3rd Class – the effort is between the load and the fulcrum. Ex. arm, broom.
Pulley – a rope or chain wrapped around a wheel. A load is attached to one end of the rope and a force is applied to the
other end of the rope. Pulleys can be fixed or moveable or both.
Wheel & Axle – consists of two circular objects of different sizes. The wheel is always larger than the axle. When effort is
applies to move the wheel, the axle turns a shorter distance, but moves with more force across a greater distance.
A compound machine is a machine made up of two or more simple machines. (Ex. scissors, meat grinders, can openers,
cars) A compound machine can be thought of as a system. A system is a group of parts working together.
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Mechanical Advantage is a calculation of how much a machine multiplies force. The input force is the force applied by
the user on the machine. The output force is the force applied by the machine to the object being worked on. It can be
calculated using the formula:
Mechanical advantage = output force / input force
Ex. An inclined plane with a mechanical advantage of 3 means that the inclined plane multiplied the amount of input
force 3 times to do the work. ( it was 3 times easier to do the work or 3 times less force needed to do the work)
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S8P4 – Waves Review
A wave is a disturbance that transfers energy without transferring matter through matter or empty space.
There are two main types of waves: mechanical and electromagnetic
Mechanical Waves are waves that require a medium to transfer energy. Ex. water waves, ocean waves, sound waves. A
medium is the material (matter) that waves travel through.
Electromagnetic Waves (EM) are waves that do not require a medium (although they can have one.) Ex. light, radio,
microwaves, infrared, visible light. It is made up of alternating electric and magnetic fields that are perpendicular to each
other.
All waves have characteristics including the wavelength, amplitude and frequency.
Amplitude – the distance from the midpoint (resting position) of a wave to its top (crest) or bottom (trough). The
amplitude of a wave determines the amount of energy being transferred. A wave with a large amplitude transfers a lot
of energy. Ex. a tsunami (large ocean waves does a lot of damage or a loud sound does damage to the ears) A wave with
a small amplitude transfers a small amount of energy.
Crest – the highest point of a wave. Trough – the lowest point of a wave.
Wavelength – the distance from any point on a wave to the identical point on the next wave. Waves with short
wavelengths transfer more energy than waves with long wavelengths
Frequency – the number of waves that pass a given point in one second. The unit of measure for frequency is the Hertz
(Hz). Frequency and wavelength are inversely related. When frequency increases, wavelength decreases. When
frequency decreases, wavelength increases.
Most waves can be classified by the way they move as transverse or longitudinal (compressional).
In a transverse wave, the particles of the medium vibrate perpendicular to the path of the wave. Ex. ocean waves, “The
Wave” at ball games) Transverse waves consists of crests and troughs.
In a longitudinal wave, the particles of the medium vibrate parallel to the path of the wave. Ex. sound waves, Slinky.
Longitudinal waves are series of close together areas (compressions) and spread out areas (rarefactions).
The part of a longitudinal wave where particles are pushed close together is called a compression. Compressions are
similar to the crest of a transverse wave.
The part of a longitudinal wave where the particles are spread out is called a rarefaction. Rarefactions are similar to the
trough of a transverse wave.
Sound travels in waves. Sound waves are mechanical waves (need a medium) and longitudinal waves. As sound travels
from the source to your ear, particles vibrate in all directions away from the source in compressions and rarefactions.
Sound and Pitch. Pitch is the property of sound that you can hear that varies with frequency. A wave with a high pitch
(high frequency and short wavelength) has a high tone Ex. Ms. Price’s voice. A wave with a low pitch (low frequency and
long wavelength) has a low tone Ex. Mr. Ennis’ voice.
Sound and Volume. The amplitude of a sound wave determines its volume (loudness). The larger the amplitude, the
louder the sound (high volume). The smaller the amplitude, the weaker the sound (low volume)
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Resonance – the effect of a vibrating object to transfer vibrations to a second object at its natural frequency.
Sound and Speed. The speed that sound travels depends on the medium it is traveling through. Sound travels fastest in
solids. It has a medium speed in liquids and it travels slowest in gases.
Sound and Reflection. When a sound wave is reflected (bounces back) it is called an echo.
Electromagnetic Spectrum – the range of all the different types of electromagnetic waves (EM) . All EM waves travel at
the same speed, but they vary in wavelength and frequency.
Radio – longest wavelength (lowest energy) Ex. transmit radio and television signals
Microwaves – long wavelength, but not as long as radio (a little more energy) Ex. cell phones, radar and microwaves
Infrared – long wavelength, but shorter than microwaves (a little more energy), can be felt as heat Ex. toaster oven coils
Visible Light – narrow section that humans can see, includes all the colors of the rainbow In order from longest to
shortest wavelength: ROYGBIV
Ultraviolet (UV) – shorter than visible light and more energy , can cause skin damage Ex. Sun
X-rays – short wavelength (high energy), can travel through soft objects such as skin Ex. x-rays
Gamma – shortest wavelength and highest energy, damaging to cells Ex. chemotherapy
Light Waves and Behavior
When light strikes an object, some light is absorbed and some is reflected. In absorption, light that enters an object stays
in the object. The absorbed radiant energy changes to heat. Light that bounces back (reflected) is the light that we see.
For example, when we see a green shirt, green light is reflected and the other colors (red, orange, yellow, blue, indigo
and violet) are all absorbed.
Reflection is the bouncing back of a wave off of a surface. The angle that light strikes a surface is called the angle on
incidence. The angle that light bounces back (reflects) off a surface is called the angle of reflection. Plane mirrors (flat
smooth mirror) produce an upright and same size image of the object. Concave mirrors (curved inward) produce an
image that is larger than the object. Convex mirrors (curved outward) produce an image that is smaller than the object.
Refraction is a change in the direction (bending) of waves as they pass from one medium to another. When white light
passes through a prism and refracts (bends), it separates into the color spectrum (red, orange, yellow, blue, indigo and
violet) Ex. appearance of a broken pencil in a glass of water.
Diffraction – the ability of light waves to bend around a barrier or the edges of an opening.
Lenses and Prisms. A lens is a transparent material that bends light. A concave lens is thinner at the center than at the
edges. Concave lenses spread light out. A convex lens is thicker at the center than at the edges. Convex lenses direct
light so that it converges at a point called the focus.
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S8P5 – Electricity & Magnetism Review
Gravity – a noncontact force that attracts objects toward one another. According to Newton’s Law of Universal
Gravitation, all objects can attract all other objects in the Universe. The amount of gravitational attraction between
two objects depends on two factors: the distance between them and the masses of each. If the mass increases, gravity
increases. If the distance between the objects increases (farther apart), gravity decreases.
A magnet is a material that exerts an attractive force on certain materials like steel and iron. Magnets can be used to
produce electricity, and electricity can be used to produce magnetism. Electricity and magnetism are related forces.
An electromagnet is a temporary magnet that consists of a current-carrying wire coli wrapped around (surrounding) a
magnetic metal core. They are useful because they can be turned on or off. Good examples of an electromagnet are the
magnets that hold the fire doors (large wooden doors) in the hallways of the school. Electromagnets are also used in
doorbells.
A magnetic force is a push or pull exerted by a magnet.
A magnet has two poles: north pole and south pole. If you cut a magnet in half, both pieces will still have a north pole
and a south pole. Each pole exerts a magnetic force. If two “like” poles of magnets come towards one another, they
repel (go away from one another). If two “unlike” poles of magnets come towards one another, they attract (come
together).
S
N
S
N
S
N
N
S
N
S
S
N
There is a magnetic field around the Earth (the Earth behaves as if it has a magnet running through the center). It traps
or repels particles coming from the sun.
Electrical energy (electricity) is generated by the movement of charged particles. Static electricity is the buildup of
charges on an object. It leads to an electric attraction that causes objects to stick to one another (static from clothes in
dryer, static on clothes that stick to you). Charged particles can attract other charged particles and uncharged particles.
The push or pull between charged particles is called an electric force. These charged particles behave like the poles of a
magnet. Like charges repel and unlike charges attract. An object with an electric charge is surrounded by an electric field
(an area which electric force is exerted).
Like gravity, magnetic forces and electric forces are universal forces. They can act between objects without the objects
touching. The magnetic and electric forces are stronger than gravity, but they act over much smaller distances.
When charged particles with like charges come together, electrons quickly move from the negatively charged object to
the positively charges object. This is called static discharge. Ex. spark, electric shock, lightning.
Electric current is the continuous flow of electric charges. Electric current must have a path or circuit to move or flow
on, this is called a circuit.
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Electric current is measured in amperes (A) or amps. Electric charges always flow from a region of higher potential
energy to a region of lower potential energy. The difference in potential energy between the two locations is called
potential difference (voltage). Voltage is measured in volts (V). A battery is a device that converts chemical energy into
electricity. In batteries the potential energy difference is produced by the positive and negative terminals.
A conductor is a material that electric charges (or heat) can flow through easily. Metals are good conductors. An
insulator is a material that electric charges (or heat) do not move easily through or not at all. Plastic, rubber, and wood
are good insulators.
Resistance is a property of matter that opposes the flow of electric current.
An electric circuit is a pathway for electric current. Charges will flow in a circuit when there is a potential difference.
Most circuits have three parts: an energy source (battery) , conductors (wire) and a load (lightbulb).
 Energy source – the source of energy that pushes a charge through a circuit.
 Load – a device that operates using the electrical energy
 Conductors – wire/material that allows the current to flow through easily.
 Switch (optional) – a device that is used to control the flow of current through a circuit.
There are two types of circuits: series and parallel. A series circuit is a single closed loop that has an energy source and
at least one load. It has only ONE path!!! The loads on a series circuit “share” the current being passed through the
circuit. For example, if a circuit has 21 amps and has three light bulbs, each light bulb will receive 7 amps and would be
much dimmer than if it were only one light bulb on the circuit. If one load fails on a series circuit, they all fail (which
means they all don’t work).
A parallel circuit is a circuit that has more than one path. The loads on a parallel circuit “do not share” the current being
passed through the circuit. For example, if a circuit has 21 amps and has three light bulbs, each light bulb will receive 21
amps and would as bright as if it were only one light bulb on the circuit. If one load fails on a parallel circuit, they others
continue to receive current because there is more path for charges to flow (which means the rest continue to work).
Extra Notes:
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Displacement method:
The volume of some objects is easy to find,
like a cube or a cylinder. The volume of some
irregular objects, like a rock, would be hard to
calculate. If you put the object in water and
measure the volume change, you have found
the volume of the object.
Vo = V2 — V1
Volume of Object
First Volume