EXAM REVIEW FOR SCIENCE
Ecology
Biotic vs Abiotic
Living (Biotic)
-
Made of cells
Reproduce
Take in energy
Eliminate waste
Life span
Growth
Non-Living (Abiotic)
-
Don’t reproduce
Not made of cells
Some need energy
Some don’t
Some eliminate waste
Some don’t
No life span
No growth
Some are man made
Organization of Life
● Atom: A particle made of protons, neutrons and electrons
● Molecule: 2 or more atoms
● Cell: Smallest unit of life, made of cytoplasm of organelles surrounded by membrane
● Tissue: Made of cells that have a similar function
● Organ: Structure consisting of cells & tissues performing a specific function
● Organ System: Organs that serve a common purpose
● Organism: A living object that is made of organ systems that work together
● Population: The number of a specific organism living in the area
● Community: Several different populations living in an area
● Ecosystem: The interaction of a community with its environment
● Biome: A large geographical area that has a unique climate that supports specific types of
animals
● Biosphere: The zone of life on Earth made by the sum of all ecosystems
Four Spheres
● Atmosphere: The atmosphere is the layer of gases that surround the Earth
○ Contains: Nitrogen, Oxygen, Carbon Dioxide, and Water Vapor
○ The atmosphere is 78% Nitrogen, 21% Oxygen and 1% other gases (like carbon
dioxide)
● Lithosphere: the rocky outer crust of the earth’s surface
○ Ex. mountains, bottom of the ocean
● Hydrosphere: all water on earth
○ Does not include water in living things
○ Ex. oceans, clouds, ice
● Biosphere: where life can exist; includes all three spheres
Cellular respiration & Photosynthesis +
Connection to carbon cycle
● Photosynthesis: the process where plants
capture energy from Sun using chlorophyll,
convert it into oxygen (O2) and glucose
(C6H12O6)
○ Equation: CO2+H2O+E →
O2+C6H12O6
○ Done only by plants (producers)
● Cellular respiration: the process of living
things using oxygen to break down sugar to
release energy to use for their bodies
(happens in the mitochondria)
○ Equation: O2+C6H12O6 →
CO2+H2O+E
○ Done by both plants (producers) and consumers
Food chains and food webs
● Food chain: {producer} > {Primary consumer} > {Secondary consumer} > {Tertiary
consumer}
○ Terrestrial ecosystems are (usually) unable to support food chains that have more
than four trophic levels
○ Aquatic ecosystems are able to support food chains with more than four trophic
levels because of their higher biodiversity
○ Side note: 90% of the energy consumed is used up/stored, only 10% of energy is
left and moves on to the next trophic level.
○ Arrows indicate transfer of energy
Relationships
● Predation - One eats the other
○ Ex. Lynx hunting a snowshoe hare
● Mutualism - Both organisms benefit
○ Ex: Bacteria in our gut and their relation to us (bacteria in our gut helps us to
digest food, and we provide them with food/shelter etc)
● Parasitism - One organism feeds on a host
○ Ex. Mosquitoes taking blood from a human
● Commensalism - One organism benefits, while one is neutral (it doesn’t affect them in a
good or bad way)
○ Ex. Moss growing on trees
● Competition - Organisms have to compete to get their food
○ Normally due to limited resources
○ Ex. Insects and humans competing for crops
The 3 cycles
● Carbon cycle
○ Carbon sinks and carbon sources
○ Results of cellular respiration and photosynthesis
○ Are stored in sinks such as trees and fossils
○ When we burn fossil fuels or cut down trees, we release lots of carbon into the air
● Water cycle
● Nitrogen cycle
Populations graphs and human population graphs (the graph with the exponential growth and
the graph with the human population over x number of years)
● Four phases: Lag phase, exponential
growth phase, transitional phase, plateau
phase
1. Lag phase: Growth is initially slow due to
only a few reproductive individuals
2. Exponential Growth Phase: More
reproductive individuals that rapidly
increase the population with few limiting
factors
3. Transitional Phase: The population growth
slows gradually due to limited resources →
competition occurs
4. Plateau Phase: Birth rate = death rate, and population growth becomes static
● Carrying capacity: the number of people, other living organisms, or crops that an
ecosystem can support without environmental degradation
● Humans have altered and increased our carrying capacity by: Removing obstacles in
possible living areas, developing technology that allows living in harsh environments,
producing more food, and creating medicine and higher standards of sanitation
● Expected human carrying capacity: 10 - 15 billion
● Limiting factors: Environmental factors that are of predominant importance in restricting
the size of a population
Sustainability
● Avoidance of the complete depletion of natural resources in order to maintain an
ecological balance for future generations
● Biodiversity: the number of variety of organisms found in an area
○ Balance of biotic + abiotic parts
○ More biodiversity near equator because of higher temp. and rainfall
● Hotspots: Areas of high biodiversity, mostly undisturbed
● Human activities can affect sustainabilities of ecosystems
○ Overhunting, invasive species, urban expansion, deforestation
Invasive Species
● Ecological niche: An organism’s place in the ecosystem
○ Food web, symbiotic relationships, habitat, breeding area, what it does to
survive…
● When a new species enters an ecosystem, it competes for a niche
● Can be brought on purpose or by accident
● Invasive species are a major threat to ecosystems
○ Change habitats, crowd out native species, damage enterprise
● 3 ways to deal with invasive species:
○ Biological — introducing natural predators of the invasive species
○ Chemical — Pesticides or Herbicides
○ Physical — Using traps and other ways to physically hunt a species
Human impact on ecosystems (for ref, look at the presentations on google classroom)
● Oil Spills
○ Leakage of petroleum onto the surface of a body of water or a stretch of land from
large oil ships
○ Can be controlled by dispersants
○ Oil is toxic, slow to break down, and difficult to clean up (but luckily it floats on
water)
○ Can be fixed by bioremediation (microorganisms that feed on oil)
● Air Pollution
○ 6 main types of pollutants: carbon monoxide, ground-level-ozone, lead, nitrogen
dioxide, particulate matter and sulfur dioxide
○ Harmful poisonous substances in the air
○ Causes: transportation, factories, electricity (direct) and products we buy
(indirect)
● Clear Cutting
○ When trees are cut down in large quantities
○ Effects: global warming, erosion, habitat destruction, loss of biodiversity
○ Selective harvesting- individual groups of trees are cut
○ Thinning- slower aging or defective trees are removed to provide more space for
healthier trees to grow
○ Shelterwood systems- after adult trees are cut down, they are left alone to provide
shelter for seedlings to grow
● Electronic Waste
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○ Electronic goods are thrown away because they no longer function properly
○ Toxic materials that leach out of electronic waste
○ E-waste affects spheres
Pesticides/Fertilizers
○ Pesticides- a chemical spray to manage and kill unwanted pests
○ Fertilizers- promotes plant growth, provides nutrients
○ Pesticides have health risks on humans
○ Bioaccumulation in food webs
Textile Pollution
○ Waste created from factories
○ Textile dyes are toxic
Overfishing
○ Fish cannot reproduce fast enough
○ Limited fish
○ Destroys industries in cities where fish is their only source of income
Urban Sprawl
○ Uncontrolled and drastic growth of urban expansion in an area
○ Human impacts- more air/water pollution harmful effects on health
Chemistry
Particle theory of matter
1. All matter is made up of tiny particles with empty spaces between them
2. Different substances are made up of different kinds of particles
3. Particles are in constant random motion
4. The particles of a substance move faster as its temperature/energy increases
5. Particles attract one another
Classification of matter
● Solutions are always transparent
● Mechanical mixture — heterogenous mixture in which the distinct materials are visibly
apparent
Physical and Chemical properties
● Physical Properties — properties that can be determined without changing the
composition of a substance
○ Ex. colour, density, melting/boiling/freezing point
● Chemical Properties — properties that are determined by changing the composition of a
substance
○ Ex. reactivity with acids, reactivity with other elements, half-life
● Quantitative: Measured properties
○ Ex. Weight, Volume, Density
● Qualitative: Described (observed) but not measured
○ Color, Smell, Malleability, Ductility
Calculating and graphing density
● Density = mass / volume
○ Usually measured g/cm3 (for solid) or g/mL (for
liquid/gas)
● Slope of a graph = density ,𝑆𝑆𝑆𝑆𝑆 = 𝑆𝑆/𝑆𝑆
○ Mass(g) is y-axis, volume(mL) is x-axis
Changes of states
➝➝➝➝➝➝➝➝➝➝➝➝➝➝➝➝➝➝➝➝➝➝➝
Atomic Model Timeline
Democritus (400 BC)
● Proposed that all matter is separated into smaller pieces
until it becomes an indivisible particle (atom)
● He thought of how boulders break into pebbles into sand, and
so on, until eventually you get an indivisible particle
● Atoms are:
○ Different sizes
○ Uncuttable
○ In constant motion
○ Separated by empty spaces
● Lacked experimental evidence
Aristotle (450 BC)
● Thought that all matter was made up of 4 basic substances, not atoms
● Fire / Water / Earth / Air
●
●
●
●
Had 4 qualities:
Hot / Wet / Dry / Cold
Lacked experimental evidence
More widespread belief than Democritus
John Dalton (1808)
● Revived Democritus’ theory
● Developed preliminary atomic theory
○ All matter is made of atoms,
which are indivisible and
indestructible
○ All atoms of a given element are identical in mass and properties
○ Compounds are formed when two or more atoms are combined
○ Chemical reactions are rearrangements of atoms
● Atom resembles a billiard ball
JJ Thomson (1897)
● Discovered that very hot material can emit negatively
charged particles (discovery of electrons)
● Used a cathode ray tube to experiment
● Negatively charged particles are attracted to the positive end
of a circuit
● Theorized that:
○ Most of the atom is a positively charged spherical
cloud
○ Negatively charged tiny particles are evenly
distributed throughout the atom
○ Also known as plum pudding model
Nagaoka (1904)
● Proposed that a positively charged center was surrounded by a
number of revolving electrons
Ernest Rutherford (1909)
● When experimenting, he shot tiny positively charged particles
(alpha particles) at a thin piece of gold foil
● Predicted that the particles would pass through, as the atom was
thought to be mostly empty
● In actuality, some particles were deflected at different angles which he thought was
caused by a collision of positively charged central mass inside the atom (discovery of
nucleus)
● Atoms are mostly empty space
● Concluded that the very large positively charged nucleus is surrounded by extremely
small electrons
● Discoveror of the proton in the nucleus
Niels Bohr (1913)
● Experiment: looked at light emitted from atoms that have
absorbed energy (looked at the light through a
spectrograph and saw that different atoms release specific
colours)
● Proposed that electrons in an atom stay in a specific energy
level called orbitals
○ The electrons could move up an orbital, with added
energy, followed by a release in the from of light
energy, but electrons could not move down
Chadwick (1932)
● Discovered neutrons
● Theorized that:
○ The atom is an empty sphere with a nucleus, containing neutrons and protons
○ Particles with 0 charge can penetrate/ disintegrate atoms
○ Mass of neutron = Mass of protons
#p, #n, #e
● Atomic number = # of protons
● Proton number in an element will never change, while electrons and protons can
● By default, electron number will equal protons, but can change into ions
● Atomic mass = protons + neutrons
○ Rounded version of atomic weight/mass number, which is an average of all
possible weights of a given elements
● Isotopes are atoms with same number of protons and electrons but different number of
neutrons
● Ions are atoms with the same number of protons but different number of electrons
○ Cation — positively charged ion (less electrons than default)
○ Anion — negatively charged ion (more electrons than default)
Bohr Rutherford diagrams
Metals vs. Non-metal properties
Metals
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●
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Lustrous
Conductive
High melting point + density
Malleable
Ductile
Solid at room temp. (other than
mercury)
Non-metals
●
●
●
●
●
Dull
Poor conductors
Not ductile
Brittle
Can be solid, liquid or gas at room
temp.
● Colorful
Periodic trends
● Moving down: Same valence electrons, but with an extra outer shell, atoms get bigger
● Columns 1, 2, 3/13, 4/14, 5/15 6/16, 7/17, 8/18 have, respectively, 1, 2, 3, 4, 5, 6, 7, and 8
valence electrons
● Moving right, increased electrons, atoms get slightly smaller due to stronger gravitational
pull from a bigger nucleus
● Alkaline Earth metals: Density and hardness increases, boiling/melting points decrease as
you go down, reactiveness increases dramatically
Chemical Family properties
● Alkali metals (group number 1):
○ P: Lustrous, silvery, soft, low density, rarely found in nature on their own
○ C: Very reactive with water, combines readily with elements/compounds,
especially halogens
● Alkaline Earth metals (group number 2):
○ P: Lustrous, silvery, quite soft (not as soft as alkali metals)
○ C: Quite reactive, substances burn bright, colourful flames
● Halogens (group number 7/17):
○ P: F and Cl are gases, Br is liquid, I and At are solids
○ C: Very reactive, forms compounds with alkali metals, poisonous in large
amounts
● Noble gases (group number 8/18):
○ P: gaseous at room temperature, colourless, tasteless, odourless, conductive
○ C: Doesn't form any compounds naturally, stable (unreactive), nontoxic (other
than radon), glows bright when electricity passes through
● Transition metals:
○ Varies
○ High density, melting point, conductive; malleable
○ Useful as catalysts, forms coloured compounds
● Lanthanides and Actinides:
○ P: Paramagnetic, bright silvery
○ C: Radioactive, some react to oxygen
Flame test
● Different metals produce different colours when exposed to a flame
● Before flame:
○ Atom is in the ground state(not absorbing or releasing energy)
○ The energy is stored inside the atom
● During:
○ The atom absorbs energy causing the atom to go into the first excited state
○ An electron gains the energy and moves further away from the nucleus to a higher
orbit (energy level)
● After:
○ The atom prefers to be in the ground state so it emits the energy in the form of
light
○ The electrons move back to the original orbit.
● High Energy ← VIBGYOR → Low Energy
○ Strontium chloride- red
○ Lithium chloride - red
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Calcium chloride - orange
Sodium Chloride - orange-yellow
Barium Chloride - yellow/green
Copper - turquoise
Potassium Chloride - purple
Gas tests
● Testing for hydrogen: Ignite wooden splint, pour H2 gas
○ If splint extinguishes with a “pop”, there is hydrogen
● Testing for oxygen: Ignite wooden splint then extinguish (glowing splint), pour O2 gas
○ If splint reignites, there is oxygen
● Testing for carbon dioxide: Ignite wooden splint, pour CO2 gas
○ If splint extinguishes, there is carbon dioxide
Molecular compounds – drawing, formulas, naming, properties
● Molecular compounds--formed with a covalent bond
○ Covalent bond--occurs between 2 nonmetals; they share electrons
○ Covalent bonds can be single, double or triple bonds
● Only occurs with two nonmetals
● Naming:
○ (Prefix) + “Element one” + (Prefix) + Element Two + “-ide”
○ Prefixes: one-mono, two-di, three-tri, four-tetra, five-penta
○ Ex. Dihydrogen Monoxide for H2O
○ Exception: do not use mono for the first element in the name
○ Ex. Nitrogen Trihydride for NH
Ionic compounds – drawing, formulas, naming, properties
● Ionic compounds--formed with ionic bonds
○ Ionic bonds--occurs between a non-metal and a metal; the metal loses (an)
electron(s) from the non-metal
○ **when naming, ionic compounds do not use prefixes
○ Ex. NaCl
○ Zero sum rule: charges of all the atoms involved in compound add up to 0
Uses of elements and relate properties to their use
Hazards and Benefits of compounds and relate properties to there use
CFCs
● CFC stands for chlorofluorocarbon and is also known as Freons
○ They are halocarbons, which has carbon and halogen atoms
○ Non-flammable, tasteless, odourless, chemically stable
■ boiling points close to zero degrees, which make them good as refrigerant
gases
● Original Use of CFC: refrigeration units and spray can propellants
● Uses:
○ Before they used to use ammonia, methyl chloride and sulphur dioxide as
refrigerants, but as they are toxic, it was quickly replaced with CFCs
○ After World War II, they were used as propellants for bug sprays, paints,
hair conditioners and other healthcare products
● CFCs can be a source of inorganic chlorine in the stratosphere after their photolytic
decomposition by UV radiation, causing some of the chlorine to destroy the ozone in
the stratosphere
○ 100,000 molecules of ozone can be destroyed per chlorine atom, which lets UV-B
reach the Earth’s surface
● Non-toxic and non-flammable to humans - 2 properties why we believed it was safe
○ They were chemically unreactive, with low boiling points so they could easily
turn into gases and were insoluble in water
● Danger
○ Break down and destroy the ozone layer of the Earth. CFCs also traps in heat and
causes the Earth to warm up, contributing to global warming.
○ When evaporated, the oxygen free radical will be released which destroyed the
ozone layer
Diamonds
● The highest thermal conductivity of any natural material
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Hardest known natural substance
Not brittle
Chemically resistant
Composed of carbon
Diamond mining provides jobs in Northern Ontario communities
○ High paying industry
Yields tens of millions paid in taxes and royalties to the Ontario government
Mercury, lead, benzenes, arsenic, chromium, lead, manganese, dioxins, furans and a
number of other highly toxic compounds are released when smelting
The energy used by the mining industry represents 7% of Ontario’s industrial electrical
power use
Pollution in many ways
DDT
● DDT is a pesticide that was very commonly used
● tasteless, and almost odourless crystalline chemical compound
● Dichlorodiphenyltrichloroethane is what DDT stands for
● Concentrates in the body fat of animals:
○ It is lipid-soluble ( the capability of a substance or compound to dissolve in lipids,
fats, or oils )
● Long-range atmospheric transport and the accumulation of the chemical in soil, water and
snow
Peroxide
● Peroxide breaks the chemical bonds in your hair, which release the sulphur that makes up
the odour of hair colour
○ As the melanin is decolorized, it allows for another chemical to bond and change
the hair’s colour
○ Peroxide can also be used in small amounts to help dye stick better, without
actually lightening your hair much, but instead breaks the chemical bonds so
colourant molecules can easily get into your hair shaft
Sodium Polyacrylate
● Sodium polyacrylate, also known as waterlock, is a sodium salt of polyacrylic acid
● Broad application in consumer products
● Used in/as:
○ Potted plants and soils to allow them to retain moisture
○ Thickening agents
○ Diapers
○ Hair gel
○ dissolves soaps in industrial processes
● It is useful because:
○ it can absorb and hold onto water molecules
○ It is a superabsorbent polymer has the ability to absorb as much as 100 to 1000
times its mass in water
● Largely adds to landfills
Tantalum
● Rare, hard, blue-gray, lustrous transition metal
● Highly corrosion resistant
● Located in the transition metals
● The key component in the electronics industry- used for capacitors and high power
resistors
● Valuable substance for laboratory equipment and a substitute for platinum
● Ductility- tantalum can be drawn into really thin wires
● Really low melting point- very resistant to heat (corrosion resistant) is
● An excellent conductor of heat and electricity
● Environmental costs
○ Destroying animals’ habitats
○ Areas in rainforests are overmined- destroying habitats
Kevlar
● Kevlar is a heat-resistant and strong synthetic fibre
● Used as a replacement for steel in racing tires
● Used as a reinforcing agent in the manufacture of tires, other rubber products and
protective gear such as helmets and vests
● High strength, toughness, and thermal stability
Electricity
Static vs. Current electricity
● Static electricity: when the charge builds up in one area (localized charge, used with
insulators)
● Current electricity: when the charge flows through an object/circuit (delocalized charge,
used with conductors)
Law of electrostatic charges
● Opposites attract each other
● Same charges repel
● Charged and neutral attract
3 ways to charge an object (contact, friction, induction)
● Charging by contact: When 2 objects (one charged and one neutral) touch each other.
The end result of charging by contact leaves both objects with the same overall charge.
● Charging by Friction: When 2 objects rub against one another. Depending on the
electrostatic series, the objects would gain a certain charge
● Charging by Induction: When 2 objects are near one another (but not touching.) The end
result would leave the two objects with an opposite charge (one positive and one
negative)
Grounding
● Give electrons a pathway to go from the charged object. Grounding an object makes it
overall neutrally charged. However, the pathway of the electrons depend on the initial
charge of the object. For example, if the object is initially positively charged, the
electrons would have to flow from Earth up into the object to neutralise it. Works vise
versa when the object is initially negatively charged.
Insulators and Conductors
Insulators: Insulators are materials that are not good at conducting electricity because electrons
don’t easily flow through the material. Ex: Plastics, dry air, glass
Conductors: Conductors are materials that are good at conducting electricity, such as copper,
aluminum, gold, and humans
Lightning
● Occurs when there is an imbalance of charge between the sky and the ground
● Both the clouds and the ground could be the unbalanced one and they both can be either
positively or negatively charged
● (Example if clouds were negatively charged, with a neutral ground) The clouds would
induce a positive charge in the ground’s surface. Due to the imbalance, the excess
electrons in the clouds would discharge towards the ground, resulting in lightning.
Static electricity applications:
Lightning Rods
● Where are they used:
○ Placed at the apex (the highest or the greatest point) of a
structure and along its ridges; they are connected to the
ground by low-impedance cables
● What are they used for:
○ Used to to protect people, buildings, and other structures from
lightning
○ Protect us from lightning damage by intercepting flashes and
guiding their currents into the ground safely
○ Lightning is more dangerous as buildings become taller. Lightning can damage
structures made of most materials, such as masonry, wood, concrete and steel,
because the voltages involved can heat materials to high temperature, causing a
potential for fire
● What materials is the device made from
○ Conductive Materials for example,
copper and aluminum
● How does the device use electrostatics to
carry out its primary use?
○ Charging by induction
○ If lightning hits the structure, it
strikes the rod and is conducted to
the ground through a wire, instead
of passing through the structure
○ The lightning rod grounds the
electrons and the electrons move to
the ground
Photocopiers
● Where are they used:
○ Offices, homes
● What is this device used for:
○ Makes paper copies of documents and other visual images cheaply and quickly
● What materials are photocopiers made from:
○ Very fine black powder (toner)
○ Photoreceptor Drum- made from a photoconductive material
○ Corona wires
○ Lamp and lenses
○ Toner
○ Fuser
● How does the device use electrostatics:
○ Inside a copier there is a special drum. The drum acts a lot like a balloon -- you
can charge it with a form of static electricity.
○ Inside the copier there is also a very fine black
powder known as toner. The drum, charged with
static electricity, can attract the toner particles.
○ The drum can be selectively charged, so that only
parts of it attract toner. Where the original sheet of
paper is black, you create static electricity on the
drum. Where it is white you do not. What you want
is for the white areas of the original sheet of paper to NOT attract toner.
○ The sheet of paper gets charged with static electricity and it pulls the toner off the
drum.
○ Light reflected from blank areas on the page hits the drum and causes the charged
particles coating the drum's surface to be neutralized. This leaves positive charges
only where there are dark areas on the paper that did not reflect light. These
positive charges attract negatively
charged toner.
Electrostatic Lifting Apparatus
● Where are they used:
○ Police investigations / forensic science
● What is it used for:
○ It is used to lift dust and other matter that
would have been left behind from
something like a footprint
○ It allows crime scene investigators to
identify a person’s shoe tread left behind
at a crime scene
● What is it made of:
○ It is made of a high voltage power
supply, control unit, a nickel-plated steel
ground plane and a metalized lifting
medium
● How does it use electrostatics:
○ Foil is placed over the footprint
○ The foil is electrostatically charged, creating electrostatic adhesions and draws the
film to the surface; this induces and attracts dirt and dust from the footprint, this
allows the footprint to be seen clearly
Electrostatic Speakers
● Where are they used / What is it used for:
○ Can be found anywhere a speaker is used
○ Electrostatic speakers are used as a replacement for
traditional speakers
○ Typically lughter and more expensive
○ The speakers are lightweight and extremely thin
making them suitable for many applications that a
dynamic loudspeaker would not be suitable for
● What is it made of:
○ Conductive diaphragm panel
○ Two stationary conductive panels
● How does it use electrostatics:
○ A traditional speaker uses an electromagnet and an electrostatic speaker
○ It vibrates air using a large, thin, conductive diaphragm panel suspended between
two stationary conductive panels
■ The panels are charged with a wall outlet and produces an electrical field
that has a positive and a negative end
■ The audio signal runs a current through the suspended diaphragm panel,
rapidly switching between a positive charge and a negative charge
■ When the air vibrates, it produces
a clear, extremely accurate sound
Electrostatic Spray Painting
● Where are they used / What is it used for:
○ Used to replace traditional spray painters
■ They produce an even coverage
and a strong bond between the
paint and the object that is being
painted
■ They save paint by having a high transfer efficiency
■ Produces a very uniform paint thickness
● What is it made of:
○ Spray gun
○ Paint hoses
○ Grounding cable
○ 2 types of adapters
● How does it use electrostatics:
○ The systems apply the charge in the barrel of the spray painter gun
○ Paint is then propelled through the gun, rubbing against the side, and gaining a
static electric charge as it moves
○ The paint particles all have the same charge, they repel each other, and attracts to
the neutral object being painted
■ This helps to distribute the paint particles evenly and get uniform coverage
○ Usually the object being painted is metal and grounded so that the paint will be
attracted to the object
■ This makes the possibly toxic
particles less likely to stay in the
air.
Electrostatic Precipitator
● Where is it used:
○ It is used by many power stations, as the amount of smoke they produce requires
electrostatic precipitators in order to be able to prevent a large amount of
unreacted carbon to be released.
● What is it used for:
○ The process of burning fossil fuels releases smoke, consisting of tiny particles of
soot. Unburned particles of carbon are pulled out using the electrostatic
precipitator, leaving clean, hot air to be
released. Without removal of unreacted
carbon, it can damage buildings and
harm human health. It is used for
pollution control.
● What is it made of:
○ A row of thin vertical wires + stack of
large flat vertical metal plates
■ Maybe uses metal as it is a good
conductor, allowing the electrons
of the unreacted carbon to easily
pass through
● How does it use electrostatics:
○ Smoke passes through negatively charged plates, and the particles become
negatively charged through conduction.
○ The charged particles then pass positively charged plates which attract the
negatively charged particle.
○ The particles then fall onto collection plates, which will later on be safely
disposed of
AC/DC Power Sources
Alternating Current
● Electrons reverse directions at regular intervals
● Used in power supplies
Direct Current
● Electrons flow in one direction
Parallel and series circuits
● Series circuit: Only one pathway for electrons to travel
○ Current at all points = total current
○ Total voltage = V1+V2+...
○ Total resistance = R1+R2+...
● Parallel circuit: More than one pathway for electrons to travel
○ Junctions are points where the path can split
○ Voltage at all points = total voltage
○ Current = C1+C2+...
○ 1/RT = 1/R1 + 1/R2 + ...
Calculating current, potential difference and resistance
● Ohm’s Law: R = V/I (resistance = voltage/current)
● The slope of the graph of potential difference vs. current = resistance
● For circuits:
○ Ammeter (series) measures current
○ Voltmeter (parallel) measures voltage
○ Ohmmeter (parallel/series) measures resistance
6 circuit laws
● Kirchhoff's Current Law (Current in Parallel)
○ Total current In = Total current out
● Kirchhoff's Voltage Law (Voltage in Series)
○ Total voltage rise - Total voltage drop = 0
● Law of Conservation of Charge (Current in Series)
○ Electric charge is neither created nor lost in an electric circuit, nor does it
accumulate at any point in the circuit.
● Law of Conservation of Energy (Voltage in Parallel)
○ As electrons move through an electric circuit they gain electric potential energy in
sources and lose electric potential energy in loads, but the total energy gained in
one trip through a circuit is equal to the total energy lost
Power, cost and efficiency
● Power = E/△t (watt = joule/sec)
● △E (cost) = P(△t) (cost = kWh * cost per kWh)
● Efficiency = energy output/energy input * 100%
Sources of energy
● Renewable sources: Wind, solar, geothermal, hydro, tidal, biomass
● Non-renewable sources: Fossil fuels (coal, gas, oil), nuclear
Astronomy
Tools that help us view celestial objects (Reflecting vs Refracting Telescopes)
● Celestial Object - Any natural occurring object that exists in space.
● Refracting Telescope - A simple tube with a lens at each end. The lenses refract (bend)
the light into the eyepiece.
● Reflecting Telescope - Instead of lenses mirrors are used to bend and focus the light to
form the image and send it to the eyepiece.
● Space Telescopes - Earth's atmosphere bends light which makes images from telescopes
unclear
○ Therefore, telescopes in space are much more powerful
● Hubble Space Telescope (HST) is the most versatile and largest space telescope, soon to
be replaced by the James Webb telescope
Kepler’s 1st and 2nd law
● Kepler’s 1st Law--states that planets orbit in an elliptical pattern with the sun as a foci
● Kepler’s 2nd Law--states that if the area of distance that the planet travels relative to the
sun is the same, than time taken would also be the same. Keep in mind that planets orbit
faster as they get closer to the sun, and they orbit slower moving away from the sun.
○ If dx > dy but both take the same time, areax = areay and vx > vy
Nebula Theory
● Solar system began as a huge cloud of dust, ice, gas, and solids
○ Gravity clumps some gas together, eventually forms a big clump
○ This clump forms a star (the Sun)
○ Planets are formed around the star, pulled by its great gravity
○ The closer planets are rocky
○ The outer planets are gaseous (not enough gravity)
● Explains 3 main things about solar system:
○ Why planets all orbit the same direction
○ Why the solar system is mostly flat
○ Why terrestrial/gas planets exist and their composition
Geocentric and heliocentric models
● Geocentric model: Where the earth is the center of the solar system
○ Proposed first by Copernicus, but ignored
○ Proved further by Galileo and his telescope
● Heliocentric model: Where the sun is in the middle of the solar system
○ Popular until the 1600’s
Retrograde motion
● The apparent motion of planets switching
directions in the sky/ looping around
● Caused because Earth orbits faster than
Mars
● Major proof of the heliocentric model
Inner Planets
● Small-ish planets made from rock |
“Terrestrial” planets
○ Mercury
■ 0.39 AU from the Sun
■
■
■
■
■
1/3 the size of Earth
1 yr = 88 earth days
1 day = 59 earth days
Smaller than our moon
Very thin atmosphere
↳ Results in huge temperature differences between day (400°C) and
night (-180°C)
■ Covered in craters because not enough atmosphere to burn up asteroids.
○ Venus
■ 0.72 AU from the Sun
■ Almost same size as earth
■ 1 year = 225 earth days
■ 1 day = 243 earth days
■ Hottest average temp – hot enough to melt lead (462°C)
■ Rains sulphuric acid
■ Volcanoes and lava flows cover the surface
■ Incredibly high atmospheric pressure – if you were to land on Venus, first
you would be crushed, then cooked!
■ Same amount of gravity as earth
■ Brightest planet in the sky
○ Earth
■ 1 AU
■ 1 year = 365 days
■ 1 day = 24 hours
■ Home to the only life we know in the universe
■ Only planet known to have liquid water. (75%)
■ Pleasant temperature for life (~20°C)
■ Has 1 moon (that causes ocean tides)
■ Ozone protects against UV
■ The tilt of the Earth’s rotational axis (23.5 degrees) is what causes seasons
○ Mars
■ 1.52 AU from the Sun
■ About ½ size of earth
■ 1 year = 686 earth days
■ 1 day = 24.4 earth hours
■ The red planet – due to iron oxide
■ Has a volcano 3X higher than Mt.Everest
■ Had liquid water at one time.
↳ No water now, maybe some ice in poles.
■ Atmosphere made of CO2
■ Has 2 moons
■ Average temp of -55°C
Asteroid Belt
● Lies between Mars and Jupiter
● Lots of small chunks of rock, some are quite large.
● May have been a planet that failed to form properly.
● Most of the asteroids are not solid – more like bundles of rock.
Outer Planets
● Very large balls of gas (“gas giants”) | May have small rocky cores, but this is unknown
○ Jupiter
■ 5.20AU from the Sun
■ Largest planet = 1,321 x Earth
■ 1 year = 11.9 earth years
■ 1 day = 10 hours
■ Great Red Spot
● As large as 3 Earth's
● Hurricane-like storm
■ Has 69 moons
■ Average temp -145°C
■ 2nd brightest planet in the night sky
○ Saturn
■ 9.54 AU from the Sun
■ 9.5 x size of earth
■ 1 year = 29.5 earth years
■ 1 day = 11 hours
■ Rings are ice particles
● Range from speck size to size of a house
● As thin as 10 m
■ At least 62 moons
■ Average temp -178°C
■ Not very dense – would float in water!
○ Uranus haha
■ 19.18 AU from the Sun
■ 4 x size of earth
■ 1 year = 84 Earth years
■ 1 day = 17 hours
■ Has a ring system, but not as prominent as Saturn.
■ Green-blue colour
■ Unusual rotation – it spins on its side
■ 27 moons
■ Coldest planet at -224°C
○ Neptune
■ 30.06 AU from the Sun
■ 4 x size of earth – same as Uranus
■ 1 year = 165 Earth Years
■ 1 day = 19 hours
■ Outermost planet
■ Dark blue colour
■ Has thin rings
■ 14 moons
■ Temp is a freezing -214°C
Formation, properties, phases of the moon
● Billions of years ago, a Mars-sized object collided with Earth
○ The ejected material formed the moon
● Properties:
○ ⅛ the size of Earth
○ 3400 km in diameter
○ ⅙ the Earth’s gravity
○ 27.3 days rotation period
○ 27.3 days revolution period
○ Therefore we only ever see one side of the moon
● 8 phases of the moon in one lunar cycle:
○ New moon → waxing crescent → first quarter → waxing gibbous → full moon
→ waning gibbous → third quarter → waning crescent → new
Solar and lunar eclipses
Solar Eclipse
● Moon is between Earth and Sun
● Moon casts shadow on Earth
● Corona is visible because the moon blocks the
sunlight
○ Not safe to look at
Lunar Eclipse
● Earth is between Sun and Moon
● More common than solar eclipses
● Safe to look at (wowie)
Properties of asteroids, meteoroids, meteors and meteorites and comets
● Comet: A chunk of rock/ice from the outer solar system, with a coma/tail
● Asteroid: A rock in orbit between Mars and Jupiter
● Meteoroid: A space rock smaller than an asteroid
● Meteor: A meteorite that enters and burns up in the Earth’s atmosphere
● Meteorite: A meteor that lands on Earth
Properties of the sun
● Solar prominences: Streams of gas that
arch back to the Sun
● Solar flares: Eruption of high energy
particles into space
● Sunspots: Cooler areas on the Sun’s
surface
Properties of the earth with respect to the sun
● 1 AU away from the sun (1 AU = 150,000,000 km)
● 365 days = 1 revolution
● 24 hours = 1 rotation
● Tilt = 23.5 degrees (on Earth’s axis)
● Earth’s magnetosphere protects us from Sun’s solar winds
○ Solar wind - deadly charged particles moving fast
○ These particles cause the Aurora Borealis and Aurora Australis
● Ozone protects Earth from Sun’s UV rays
○ Earth’s atmosphere also traps heat in, keeping temperatures moderate
Properties of stars
● Does nuclear fusion to create heat
○ Pressure of the fusion counteracts gravity
● Distances measured in light years (1 ly = 9.46 * 10^12 km)
● Magnitude = brightness
○ Apparent magnitude = brightness as observed from Earth
○ Absolute magnitude = actual brightness if all stars were placed the same distance
from Earth
● Brightness depends on 3 factors:
○ Temperature
○ Distance from Earth
○ Size
● Hotter stars are more blue while colder ones are more red
● A star’s composition can be determined by looking at its emission spectrum
○ Match colour bands to known elements
● Hertzsprung-Russell Diagram: graph that shows Brightness vs. Surface temp
● Groups of stars that resemble a shape in Earth’s sky are called Constellations
Doppler Effect and Redshift
● The Doppler effect is the an increase (or decrease) in the frequency of sound, light, or
other waves as the source and observer move toward (or away from) each other
○ Redshift = planets moving away Earth
○ Blue shift = planets moving towards Earth
Properties of Galaxies
● Galaxy - a huge collection of gas, dust and billions of stars held together by gravitational
pull
○ All these objects orbit a black hole in the center of the galaxy
● Different shapes of galaxies:
○ Spiral (Milky Way Galaxy)
○ Barred spiral
○ Elliptical
○ Irregular/Peculiar
○ Lenticular
● Milky Way:
○ Elliptical shaped with a large bulge in the centre
○ Made of more than 200 billion stars
○ Approx 100 000 light years across
○ Will collide with the Andromeda Galaxy in 4 billion years
The Big Bang Theory
● Created by Georges Lemaitre in 1927
● “Time Zero” was 10-15 billion years ago
○ All matter was compacted to one infinitely small ball (singularity)
○ The ball was extremely hot, dense and pressured
○ Suddenly expanded, hurling matter in all directions
● Cosmic Microwave Background (CMB) proves this theory
○ Leftover radiation that is uniform throughout the universe
● The universe is expanding at an accelerating rate
○ Observed from redshift of distant galaxies (moving away)
● We live on Earth that is part of
○ → Our Solar System that is part of
■ → The Milky Way Galaxy that is part of
● →The Local Group that is part of
○ →The Local Cluster (Coma-Sculptor Cloud) is in
■ →The Local Supercluster that is one part of
● → The Observable Universe from
○ → The Universe