Transcript PP180 Unit 1

Subject knowledge
Matter - download 3
Matter and the re-cycling of
materials
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<Download k3.1_2.1a Matter and Recycling> Authored by Keith
Ross, University of Gloucestershire. Accessed from
http://www.ase.org.uk/scitutors/ date created April 2006
Matter 1 – download K3.1_2.1a
April 2006
slide 1
Matter and recycling
Keith Ross
Matter 1 – download K3.1_2.1a
April 2006
slide 2
What happens to
(a) the material
(b) the atoms
when 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 ...
Matter 1 – download K3.1_2.1a
April 2006
slide 3
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
Matter 1 – download K3.1_2.1a
April 2006
slide 4
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
Matter 1 – download K3.1_2.1a
April 2006
slide 5
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
Matter 1 – download K3.1_2.1a
April 2006
slide 6
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)
Matter 1 – download K3.1_2.1a
April 2006
slide 7
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) K3.1_2.1a
Matter
1 – download
April 2006
slide 8
When you pump air into a football
• Will the football
•get heavier
•stay the same
•get lighter
30%
50%
20%
Let’s 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)
Matter 1 – download K3.1_2.1a
April 2006
slide 9
Matter 1 – download K3.1_2.1a
April 2006
slide 10
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
10%
30%
60%
(burnt up or because now a gas)
(% 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)
Matter 1 – download K3.1_2.1a
April 2006
slide 11
The Candle
What is the
function of
the wick?
To hold what is
burning
What is the
function of
the wax?
To burn - it's
the actual fuel
Matter 1 – download K3.1_2.1a
To slow the
rate of burning
April 2006
slide 12
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
Matter 1 – download K3.1_2.1a
April 2006
slide 13
The periodic table shows only elements
ref: page 3
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April 2006
slide 14
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”
Matter 1 – download K3.1_2.1a
April 2006
slide 15
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)
• Matter
salts1 (ionic)
– download K3.1_2.1a
April 2006
slide 16
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.
Matter 1 – download K3.1_2.1a
April 2006
slide 17
Indestructible particles
Changing a ‘face’ into a ‘car’ using the
same particles. Bulk matter changes, but
the underlying particles are the same
Matter 1 – download K3.1_2.1a
April 2006
slide 18
Animation of melting & burning
• Many people think that 'atoms' melt,
burn, expand and dissolve, just like the
real materials do.
• CD-rom animation
Matter 1 – download K3.1_2.1a
April 2006
slide 19
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
Matter 1 – download K3.1_2.1a
April 2006
slide 20
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.
Matter 1 – download K3.1_2.1a
April 2006
slide 21
4th idea - Natural material
cycles
• CD-ROM water cycle
• carbon cycle
• Rock cycle works over geological time
Matter 1 – download K3.1_2.1a
April 2006
slide 22
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.
Matter 1 – download K3.1_2.1a
April 2006
slide 23
6th Idea:
Carbon - the element of life.
• need for functional groups to make and
break chains
• Duplo model for polymers
Matter 1 – download K3.1_2.1a
April 2006
slide 24
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
Matter 1 – download K3.1_2.1a
April 2006
slide 25
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?
Matter 1 – download K3.1_2.1a
April 2006
slide 26
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
Matter 1 – download K3.1_2.1a
April 2006
slide 27
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
Matter 1 – download K3.1_2.1a
April 2006
slide 28
Coursework – ideas for concept map
Made from
Types of
material
Periodic table of
elements
Structure
triangle
Natural
cycles
Matter 1 – download K3.1_2.1a
Unchanging
atoms
Life processes
April 2006
slide 29