Subject knowledge Matter - download 3

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Subject knowledge Matter - download 3

• Matter and the re-cycling of materials

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k3.1_2.1a Matter and Recyclinggt Authored by Keith
Ross, University of Gloucestershire. Accessed
from http//www.ase.org.uk/scitutors/ date
created April 2006
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Matter and recycling

• Keith Ross

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What happens to (a) the material(b) the
atomswhen things are thrown away, burnt, etc?

• Rocks - glass, sand ...
• Metals - aluminium, batteries ...
• Materials from Life - sewage, paper, ...
• Plastics - bottles, bags, packaging ...
• Volatiles - exhaust gases, insecticides ..
• Ionic - corroded metals, fertiliser run-off ...

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Matter

• to understand the fate of materials discarded
  into the environment, we need to know
• the range of materials that occur
• their atomic make up.
• how they might interfere with living things

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Six Ideas

• 1. Atoms are conserved
• 2. There are 5 types of material
• 3. All made from the 100 elements of the periodic
  table
• 4. Life, rocks and climate all cycle materials
• 5. Humans do not re-cycling everything
• 6. The role of life in cycling materials

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First idea Materials are conserved

• Consider what happens when
• you change the shape of a lump of plasticene
• you crush a sugar lump to a powder
• Will it
• get heavier
• stay the same
• get lighter

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When you add salt to a cup of water

• Will the cup
• get heavier
• stay the same
• get lighter
• (see how children answered this question on next
  slide)

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When you add salt to a cup of water..
Figure 4.7 Graph showing the percentage of survey
pupils who conserved mass/weight of sugar when it
dissolved (from Holding 1987)
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When you pump air into a football

• Will the football
• get heavier
• stay the same
• get lighter

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50
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Lets see ( responses are from a group of 100
18-20 year olds who all gained a GCSE pass at
grade C or better two to four years previously)
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(No Transcript)
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When you burn rubbish

• Compared to the rubbish, will all the materials
  produced during burning (smoke, fumes, ash, char
  ...)
• be heavier
• be the same
• be lighter
• ( responses are from a group of 100 18-20 year
  olds who all gained a GCSE pass at grade C or
  better two to four years previously)

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30
60 (burnt up or because now a gas)
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The Candle
To hold what is
What is the
burning
function of

the wick?
To slow the
rate of burning

What is the
To burn - it's
function of
the actual fuel
the wax?
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When something is dumped on the rubbish tip, goes
up the chimney or down the drain, its atoms

• (a) may eventually cease to exist
• (b) may remain harmlessly in the environment
• (c) may be used by living things to help them
  grow
• (d) may remain in the environment and cause
  pollution

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The periodic table shows only elements
ref page 3
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2nd Idea 5 structures only

• The Periodic Table is for Elements
• About 100 elements make up our entire universe
• But what about the billions of compounds created
  from them?
• CDrom The Structure Triangle

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2nd Idea 5 structures only

• Pure substances (whether they are elements or
  compounds) come in only five basic structures
• metals (eg copper, brass)
• rocks (3-D giant molecular structures - eg
  granite, bricks)
• life-polymers (polymeric/fibrous giant molecular
  structures - eg wood, nylon)
• volatile materials (gases, most liquids and
  volatile solids)
• salts (ionic)

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3rd Idea Matter is made of particles. Explains
conservation (1st Idea)

• Atoms as unchanging particles amid change
• Duplo model of unchanging particles called atoms
• These atoms form the basis of an understanding of
  all the changes we see about us.

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Indestructible particles

• Changing a face into a car using the same
  particles. Bulk matter changes, but the
  underlying particles are the same

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Animation of melting burning

• Many people think that 'atoms' melt, burn, expand
  and dissolve, just like the real materials do.
• CD-rom animation

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Figure 2.1 A watery solution (drawn by a year one
B.Ed student) From Ross Lakin and Callaghan
(2000) Teaching Secondary Science London David
Fulton
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2nd Idea (again) - the Structure Triangle for
elements and compounds

• Bonding depends on the arrangement of the
  electrons on the outside of atoms.
• These outer electrons help to 'glue' atoms
  together.
• A study of chemical bonding allows us to account
  for the five categories of substances established
  earlier.

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4th idea - Natural material cycles

• CD-ROM water cycle
• carbon cycle
• Rock cycle works over geological time

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5th Idea What happens to the substances we
discard into our environment?

• CD-ROM Industrial cycle
• How will rubbish we throw away affect living
  things?
• We need to look at how life works from a chemical
  point of view.

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6th Idea Carbon - the element of life.

• need for functional groups to make and break
  chains
• Duplo model for polymers

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Living cells make enzymes

• if a cell can make an enzyme, it can perform a
  specific reaction.
• enzymes are polymerised amino acids 'folded up'
  in a specific 3-D shape.
• this shape allows them to act on just one sort
  of molecule.
• DNA, the genetic code, has the blueprints for
  making all enzymes

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Life builds up and breaks down structures

• builds up protein, DNA, fats, cellulose, starch,
  etc and digests them (all using enzymes)
• the petrochemical industry also makes and breaks
  substances like nylon, polythene, insecticides,
  etc
• so why is it that only life structures are
  biodegradable?

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Non-Biodegradable materials

• Without an enzyme, carbon compounds can only be
  broken apart by
• ... high temperatures and,
• ... (sometimes) bright sunlight.
• life has not (yet) evolved to produce enzymes
  which can break up manufactured organic compounds

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Other discarded materials

• Consider each of the five substance types in
  turn
• What happens to them, and their constituent atoms
  when discarded?
• If life cannot use the material we must develop
  our own (re-)cycles for them.
• MM a load of rubbish

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Coursework ideas for concept map
Unchanging atoms
Made from
Types of material
Periodic table of elements
Structure triangle
Natural cycles
Life processes