Transcript Science Study Notes

© Andrew Newbound 2008
© Andrew Newbound 2008
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Greeks – developed model of universe –Earth at centre
Ptolemy – refined idea
Copernicus – showed the Earth was not at the centre of
the universe or the solar system
Galileo Galilei – 1st person to use telescope in
astronomy, observations supported Copernicus
Kelper – Used Brahe’s measurements to prove suncentred model, explain motion of planets in 3 laws
Isaac Newton – Introduced ‘Gravity’ the sun, moon,
planets attract each other with their gravity and their
speed stops them colliding. Model called Newtonian
model.
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Only ½ of Earth in sun at any given time
(other ½ in shadow)
 Sunshine = day, Shadow = Night
 Earth is tilted – seasons caused by this
 Year – time it takes the Earth to go around
the sun once
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People used movement of sun to show time
(before clocks)
 Sundial uses shadow to show time
 Common sundial consists of flat plate, shadow
stick/gnomon (makes shadow)
 Calendar – shows weeks + years
 Very important to ancient civilisations – seasons,
seasonal rains (crops)
 Stonehenge – Thought to be a calendar
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Moon – Earth’s natural satellite
Weak gravity, no atmosphere
Astronauts take air, water + food talk by radio
One of largest in the solar system
¼ as wide as earth
Changes in shape – phases (caused by sunlight)
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Lunar Eclipse – Moon
› Shadow of Earth moves across moon
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Solar Eclipse – Sun
› Sun blocked out by moon
› Looking at the sun can cause blindness
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Sun
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Centre
Star
Provides all energy needed to maintain Earth
Huge ball of hot gas
Energy comes from nuclear fusion reactions
 Hydrogen atoms converted into helium
 Creates lots of energy
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8 planet (not including Pluto)
› Revolve around the sun
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Moons
Asteroids
Solar system – almost flat
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Mercury:
 Closest planet to sun
 Small – little gravity
› Too weak to hold gases
(atmosphere)
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Silent (sound doesn’t
travel)
Greatest temperature
range of planets (400°C to 200°C)
Rocky
Many Craters
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Venus:
 Easily seen
 Brightest object in the sky
(sun, moon)
 Evening star = false
 Hot desert, volcanoes,
highlands, lowlands
 400°C (atmosphere)
 Atmosphere pressure = 90x
earth’s
 Rotates slowly (day > year)
› Rotates backwards (sun
rises in west, sets in east)
Earth:
 Water on surface
 Atmosphere
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Oxygen
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Formed ‘ozone’ – filters out
dangerous light from sun
Thin enough to let through
sunlight, thick enough to burn up
meteorites
Mars:
 Red planet
 Gravity – ½ Earth’s
 Thin atmosphere
 Covered with rusty red rocks +
dust
 Winds up to 100km/h
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Only known place to support
life
Blows dust into atmosphere
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Takes months to settle out
 Makes sky red
Has seasons
Polar caps – solid carbon
dioxide (dry ice)
› Melt in summer, freeze in
winter
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Largest volcano – Olympus
Mons – 700km across, 27km
high
Jupiter:
 Largest planet
 Tiny core, thick atmosphere – hydrogen + helium
 Gas giant – no solid surface
 10hrs to rotate
› Causes high winds
 Coloured bands
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Red spot – largest cyclone
Galileo Galilei – discovered 4 moons (1610), Actually
16 maybe more smaller
Knowledge - from space probe Galileo (1995-1996)
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Saturn:
 Famous for rings
› Made of rocks (dust – boulders)
› Saturn, Jupiter, Uranus + Neptune have rings
 Saturn’s – largest, Easiest to see
Gas giant – no firm surface
 Density – 0.7 of water
 18 moons – most moons
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Uranus:
 Discoed by accident (1781)
 We only see fuzzy blue-green ball
 Voyager 2 (1986) – supplies most of our
info
 Gaseous planet – no hard surface
 Highest temp is -200°C
 On its side
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Neptune:
 Most distant gas giant
 Blue-green flecked with white
 Similar to Uranus, but windier
 Winds – up to 2160km/h
 Voyager 2 – Discovered most of the info
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Pluto:
 Not a planet
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Earliest use of stars – set calendars, clocks
Time to plant crops when a star rose/sun
was in a certain location
Constellation – Group of stars that forms a
pattern
Earth spins once every 24hrs
Sky looks like it is turning (it isn’t, we are)
› One turn takes 24 hrs
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Smallest living thing – cells
 Plants + animals – made of cells
 ‘All living things are made of cells which
are always made of cells’
 Human bode – 1,000,000,000 cells
 Started as ovum, divided to 2, 4, 8
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› Called division
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Cells change shape and size to do a job
› Differentiation
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Living plants and animals from non living objects
Replaced by theory of cells
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An instrument which enable us to see
very small objects
 Compound microscope – 2 lenses
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› Magnify for 40x to 100x
Two eye pieces – dissecting
 Electron – uses electron instead of light
to produce image
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› Viewed on TV screen
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Need slide – flat piece of glass
 Prepared slide – has specimen on it
 Cover slip – thin piece of glass used to
protect specimen
 Drawing – show only main parts
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› Pencil
› Add labels to highlight important features
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Both eyes open
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Animal + plant cells
› both basic units of plants and animals,
› contain nucleus, membrane, protoplasm,
cytoplasm, vacuoles
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Organelle - Inside cell, allow it to function
Difference – jobs
Plants make own food
› Need water, carbon dioxide + minerals from soil,
sunlight to provide energy
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Animals – eat ready made food
› Cells convert food into energy
› Cells need steady supply of food + oxygen
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Made of 1 cell – unicellular, protists
Protest cells contains: nucleus, organelles
Amoeba – well known protest
› Lives in water
› Feed by engulfing prey
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Most protists don’t harm humans
› Some beneficial
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Bacteria not protists
› 1000x smaller than protists
› Lack internal parts found in protists
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Viruses – not made of cells
› Consist of chemicals found in nucleus of cells
› Eat healthy cells, take over cell to make more viruses
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Group of diseases result from
uncontrolled cell division
 Can form anywhere in the body
 Cell division out of control
 Cancer spreads
 Things that cause skin cancer are:
sunlight, smoking, fatty diet, alcohol,
asbestos, chemicals, radiation
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Cells – smallest living thing in a plant or
animal
 Plants and animals come form cells. This
is the cell theory. All cells come from cells
 Unicellular – organism made of 1 cell e.g.
protozoan
 Multicellular – organism made of many
cells e.g. humans
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Electron microscope – uses a beam of light
to produce an image
Magnification – how many time larger an
object looks compared with its real size
Resolution – amount of detail you can see
Total Magnification = eyepiece x objective
lens
Organism – living thing
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Animal Cells
Vacuole
nucleus
Cell Membrane
Vacuole
Plant cells
Chloroplast
nucleus
Cell wall
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© Andrew Newbound 2008
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Energy:
› Makes Everything happen
› Needed by everything moving
› Without it = no change, no movement
Energy in our bodies comes from chemicals
in the food we eat
 Our bodies convert chemical energy into
the types of energy our bodies need to stay
alive
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Kinetic:
 Moving
 Abbreviation: KE
Potential (PE):
 Stored
 Types:
› Gravitational (GPE)
› Elastic (EPE)
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Heat
 Moving particles
Sound :
 Vibrations
Electrical:
 Carried by electricity
Solar:
 From the Sun
Light:
 Sun, light bulbs
Electromagnetic:
 Radio waves,
 Microwaves
 Television waves
 Light
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Nuclear:
 From atoms
Energy changes:
 Energy conversion
 Energy transformation
Car: chemical (petrol) to kinetic
 Wheat field: solar to chemical (food)
 MP3 Player: chemical (batteries) to sound
 Telephone: Sound to electrical to
electromagnetic to electrical to sound
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Carried by electricity
Transformed from kinetic energy (of the generator)
or chemical energy (in the electrochemical cell)
Clean + convenient
Can only flow through a conductor
Insulator – stops the flow of electrical energy
Transformer – changes the amount of electrical
energy
Flows through an electrical circuit (pipeline for
electricity)
Flows from positive (+) to negative (-)
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Moves from one substance to another
› From hotter to cooler
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Through solids – conduction
› Conductors – allow the movement of heat
› Insulators – stop the movement of heat
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Through liquids and gases – convection
› Tiny currents (called convection currents) carry
the heat
› Warm air moving around a room – convection
current
› Heat is circulated in a saucepan of soup by
currents in the soup
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Important in our lives
E.g. ovens, toasters, electrical radiators
Heat from sun come by radiation
Hot objects radiate heat to their
surroundings
Vacuum flask – keeps heat in or out in all
ways of movement
› 2 layers of metal have a vacuum between them
› Heat can’t pass by conduction/convection
› Being shiny reduces the heat lost by radiation
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Mainly from:
 Coal, oil and natural gases (fossil fuels
(made from fossils))
 Coal – plants
› Mined in open pits/underground
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Oil/Gas – Tiny ocean animals
› Huge rigs dig down
› Bass strait
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Fossil fuel will dry up soon
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Hydroelectricity:
 Water flowing downhill
 Potential-kinetic
Solar:
 Sun
 Solar
Wind:
 Moving air
Tides:
 Moving water
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Geothermal
 Heat inside the earth
Hydrogen:
 Chemical
Biological Fuels:
 Plants
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Water:
› Needed by all living things
› Makes up 70% of our bodies
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How to detect water:
› Copper sulphate, sodium chloride
 Dissolved then soaked into paper
 Changes colour if there is water (positive)
 Stay the same if there is no water (negative)
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Ice, water, gas – different forms of water
› Phases of water
States of matter: solid, liquid, gas
 Steam – liquid with small drops of water
 Each change in state is given a name
 Liquid boils – changes into a gas
(boiling/vaporisation)
 Gas cools – changes into a liquid (condensation)
 Solid heats up – changes into a liquid (melting)
 Liquid cools – Turns into solid (freezing/solidification)
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Solvent – liquid that dissolves substances
Solute – substance that is dissolved
Solution – a liquid with a solvent dissolved in it
Insoluble – a substance which does not dissolve
Crystallisation – the process of undissolving
› As the solvent evaporates, the solvent is left behind
 Solute mostly appears as crystals
 Fast evaporation – tiny crystals
 Slow evaporation – large crystals
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Water is a good solvent
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Separating a solvent from a solute (keeping both
substances)
Solution is boiled, steam collected, cool and turned
back into its original state
Heated with electric hotplate/Bunsen burner,
vapours cooled with Liebig condenser or glass tube
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Water is vital for life, every living thing needs it
Most of water impure (sea water/bore water)
Water supply – system of pipes supplying us with
water
Dams – store water
Water must be treated and purified (making water
pure)
› Clay and mud are removed, microscopic life is killed
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Collected in Dams
Purified
Comes out of taps
Stored in reservoirs
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Aim of water treatment – to make water
clean, safe and pleasant to drink
 Filtered to remove solids
 Treated with chlorine or ozone to remove
microscopic living things
 Fluoride added
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1. Sieved
3. Filtered
2. Alum added
4. Chlorine added
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Sewage:
 Contains human waste, food scraps, oils,
detergents, soap
 Treated before released into
environment
1. Filtered, allowed to stand in ponds
2. Stirred, air bubbled in
3. Filtering, water plants growing
4. Chlorine gas, ozone used as disinfectant
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Salt and fresh water have different
properties
 Salt water denser
 Salt water turns orange when burnt
 Pure water doesn't conduct electricity,
salt water does
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© Andrew Newbound 2008