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Subject knowledge Matter - download 3

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Title: Subject knowledge Matter - download 3


1
Subject knowledge Matter - download 3
  • Matter and the re-cycling of materials

This document can be freely copied and amended if
used for educational purposes. It must not be
used for commercial gain. The author(s) and web
source must be acknowledged whether used as it
stands or whether adapted in any way. ltDownload
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
2
Matter and recycling
  • Keith Ross

3
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 ...

4
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

5
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

6
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

7
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)

8
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)
9
When you pump air into a football
  • Will the football
  • get heavier
  • stay the same
  • get lighter

30
50
20
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)
10
(No Transcript)
11
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)

10
30
60 (burnt up or because now a gas)
12
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?
13
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

14
The periodic table shows only elements
ref page 3
15
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

16
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)

17
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.

18
Indestructible particles
  • Changing a face into a car using the same
    particles. Bulk matter changes, but the
    underlying particles are the same

19
Animation of melting burning
  • Many people think that 'atoms' melt, burn, expand
    and dissolve, just like the real materials do.
  • CD-rom animation

20
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
21
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.

22
4th idea - Natural material cycles
  • CD-ROM water cycle
  • carbon cycle
  • Rock cycle works over geological time

23
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.

24
6th Idea Carbon - the element of life.
  • need for functional groups to make and break
    chains
  • Duplo model for polymers

25
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

26
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?

27
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

28
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

29
Coursework ideas for concept map
Unchanging atoms
Made from
Types of material
Periodic table of elements
Structure triangle
Natural cycles
Life processes
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