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 ● ● ● ● ○ 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 ● ● ● ● ● ● 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 ○ ○ ○ ○ ○ 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 ● ● ● ● ● ● ● ● ● 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