University of Nigeria
Virtual Library
Serial No
Author 1
NWAGU, Eric K. N.
Author 2
NZEWI, Uchenna M.
Author 3
Title
Strategies for Teaching Components
of the Environment to Secondary
School Students
Keywords
Description
Strategies for Teaching Components
of the Environment to Secondary
School Students
Category
Education
Publisher
University Press Plc
Publication Date
Signature
Dr Michael
Okoye
Digitally signed by Dr Michael Okoye
DN: CN = Dr Michael Okoye, C = NG, O =
University of Nigeria, OU = University Library
Reason: I have reviewed this document
Date: 2008.06.11 02:24:32 +01'00'
Wclcomr Address by STAN ~ ~ ~ : v ~ I - o I ~ I I ~ ~ ~I I ~~ ;~I IC
I?-qcct I:~irector,Professor Peter Ol<cbukola
I G I ~ I O I ~
! -30
Dr. Erie K.N. Nwagu
and
Prof. Uchenna M. Nzewi
Sub-Dept. of Science Education, U~iivcrsityoS Nigeria, Nsultka
Pp'h9f
PJ'jtf is POMP?
The cnvironment is so complex that it appears difficu!t to conceptualize
wholistically, some students in certain situations pcrccive only thc
atmosphere as their cnvironment some others 3s their environment,
some others define the conccpt fi-om only the lithospl~ericperspective.
More observant ones describe tilcir cnviron~:~entlimn the point o!'view
of n~aterialswithin their immediate surrounding. A good understanding
of components of thc cnvit*o~;ment, their char-actcristics, and the
mteractions alnong the clements of thc componctits would cnable
students develop friendly disposition towards thc cnvirolme~it.
Illis unit presents the aspects of thc colnponcnts of thc cnvironment
which swondary school studcnts should stildy and t&e appropriate
instructional strategies for teaching them. .
-
7
AAer completing this unit, you should bc able to:
identify the aspects of the cornponcnts o f the cnvironmcnt to
flj
bc taught to secondaty school stuclcnts;
112
t
(!ij
(iii)
(iv)
identify the clcmcnts t11at iiiake up the coniponents of the
environment;
explain the need for the preservation of the environment in a
clean and balanced state; and
discuss the strategies of the components or the environment.
The atmosphere is the layer of gases that envelop the earth and cover its
surface. The gases that make up the atmosphcre is held to the earth's
surfacc by the gravitational force of thc carth. The gases are
concentrated close to earrh's surfacc but decrease in density /
concentratidn with altitude. ?'he atmosphcsc cxtcnds to about 10,000
Kilon~etresfrom earth's surface. I-Iowever '-10%)ol' atmospheric matter
lies within 16km altitude. Much of the dynamics of the atmosphere,
which influence the lives and activities of living things occur within the
lower 3 kilometres of the atmosphcre.
The atmosphere has gaseous, solid and liquid colnponcnts. l'hc nlajor
gases are: Nitrogen, Oxyger,, Argon and Carbon IT Oxide. Nitrogen,
which accounts for 78.08% of' dry atn~osphericgases by volun~cacts as
a neutral filler because it does not react quite readily with other
elements in the environment.
Moreover, atmosphcric Nitrogcn is drawn and converted to nitrite and
stored in the nodules of' legumes by iiitrogcn fixing bacteria.
Oxygen accounts for 20.95%)of dry atmosphcric gases by volume. It is
tllc gas that sustains lilc, and supj~osLscoml~~rst~on
and other forms of
oxidation reactions. A ninials t altc i n o sygcn Sol- t hcir respiration and
give out carbon 111 oxide. ~rllich plants in turn take in for
photo:;ynthesis and givc out oxygei1. Carbon iV oxide occupies 0.03%
of the volume of thc atmosphcre. It helps to maintain tlie temperature of
the atmosphere b ecause i t i s capable o r absorbing hcat from passing
solar energy spcctrum (cf. Ezeudu, 2002).
The inert gas Argon accounts for 0.93% of the dry atmosphere by
volurx, and is believed to be ensuring high luminosity of sun's energy
rays /)assing through tlie atmosphere. There are other gases that appear
I ~ tsaccs.
I
Outside gases, thcrc are tiny solid particles in the atmosphere
collcctivcly cnllcd atmospheric acsosols. 'i'hey include: dust particles.
pollcn grain, carboil soot, ad^, pasticlcs ol' sca salt, and sposcs of
113
What to t t a c h Scconrlat-y School Stritlcnts i l l ) o ~ tI-lyclrosphere
1 Iytil-ospl-tcrei s t he w atcr c::;~l~i>(>ni'.~it
o 1' t Ilc ca~.tIl.I I o ccurs a s watcr
i>o,clicscspccinlly on the si~rl'acco f tlic earth. 'l'lic watcr hodics arc i n
tltc ( i x m i,l' c~ccar-IS,
s c m ; I;tltcs, po~icis,i'iw-s, unclcl-gr-aunt! watcr, ctc.
~llc;.ch c 1 0 ice hct-gs o ~ Ii
sc;~s.occ:i~ls;111(l I ; I ~ C Sice
: COVCI- 0 1 1
I ~ I C J U I I ~ : \ I~~> IC ; ~ I \ S i111tl 1 7 0 1 ~ 1 i .I ' C ~ I O ~I1I1 S
1 c l:S I I O \ \ / CO\.L,I. 011 ~ C I I I ~ K I . ~ I\ (, C\ ! I I I ~ c ~
I:III;.~S. 111 thc ~ w c l : : 01. I\V(:I);~ (2000),l ~ y d ~ ~ ~ x i accoi~~its
~ ) l ~ c ~ - (ix.
c dm~t
70'1.h 01' earth's su~-I.ai:t~
covc~rgc.
'I'he lithosphere is tlic earth's crust. It is thc outer-most layer of rocks
on e artll. the thickness o f t he litliosphere v arics f'roln rive tcilo~iietres
(under ocean floors) to 48 ltilometres in continental highlands). The
stru~tureand con~positionof the layers of thc lithosphere may not be
for the students at this tinie. 'I'l1c Socus siio~~id
be on the aspects of tlie
lithosphere that directly influence liumali livcs and activities.
~it"1;os~hereis made up of rocks. The rocks differ in chemical
con~position,colour, density, size and shape of grains or crystals, etc.
some of tlie roclts arc useful in industrial processes and are therefore
mined as minerals. Otl~erroclts closc to the surface of the earth are
weatliered and so~ncti~nes
eroded, transpor-tcd and deposited elsewhere.
The weathered rocks constitu t c the mincral mat tcr component of soils.
Soil is the "thin outer layer of the earth made up o f a mixture of mineral
and organic materials, air and water formed from the underlying rocks,
plant and animal ~naterialsby various physical, clicmical and biological
processes" (Areola, Iruegbc, Ahmejd, Adelelte PL Ceong, 1992). Soils
can be classified either according to sizcs of soil grains (e.g. sandy,
Loamy and Clayey soils) or- to thc structure ol' tlic soil (e.g. I,aterite,
1'od;:ols. Chcri~ozems,ctc).
'I'he rclicf and topography arc other aspects oS thc litl~osphei-ethat
directly influences human livcs. 'i'lic two hctc~rs affect soil
devclopnicnt and consequently agricultural and other cconomic
activities. rl'liey also affcct cornmunicatior~,clr-ainagc and scttlcmcnt
patterns in an area.
.
Pi-oject:P~.ojc?ctas instructionai stratcgy involvcs the students in
fairly long search for thc sohtiori or a pro171~111s01- answer to
questions. For instance, students ca;1 bc gt-oupcd and assigned
i c i t 1andsc:q)e o r rci ief arcas to study tlic rocks and soils.
~ differences in soil and rock types; the
Thcy can C ~ C S C I . ~ ~t > C! !om1
soil prolilc; iiic ~.clationsliipbetween ~.ocks,soils and vegetation.
The students present thcir f'ir~dingsin pi-r!jccts reports.
2.
Lectzrre: Lecture ~-itetho(with suitable inst~wtionalstrategies like
questioning and conct \ t map can acliicve a lot i i i teaching t l ~ c
topic, lithosphere.
Thc+lictionary of geography j l h c i ~ a n a i ~1974)
,
i!clincs hiosplicre as an
Ill?.
ccologic,al tcmi rncailir~gthe i721.t 01' [llc c*ar-111,\\lhicli s~iI7j~ol'[s
B i o q h r c is the world of lifc, whicl~111ciu(1csthc I(iwcr at~i?ospIicrc,tile
biosphere, and the lithosphere to a dcpth helow. whicli t l w c I S no
organic life.
Figlw 1:
Graphical Repi-csc~~tat
ior~o I' the C O I T ~ ~ I O of'
~ I I-luniaii
~II~S
Environment
1,ifc is possible ~r11cret'ricrc is a ccn~bincdPI-cscnc:c of air-, watcr and
mineral matter. 'I'he various splicrcs o l' klic cnvi I - ~ ~ I I I I tC I are
I
not
mutllally exclusive. ri'l~e intcrscction of. thc t111-ccfsp11c1-cs
is ilic
*
biosplm-c. Otlier questions to be cxplol-cci are:
t
I low docs fish obtain oxygen'!
I-low do othci- ac~unticanrnials ol~tnir~
tl~cil-osygcn'!
I-Iow do birds of thc air obtain whiakc~ 10dl I I I I ~ ' !
Does fish rcqul re 1ithosphc1-cto survi vc'!
Why is organic marnirc bcttcr than chcnlical fertilizer for
fartni ng?
What are the classes of 1Ivr11gthings ill t i l t I-)~osP~IcI~L"!
What are the types of relationships among living things in the
biosplicrc?
'
5'7:41V L;tr\~i/~o~rirr~~r~~(~I
I ~ , ' ( k ~ ~ (Sei-ie.s
~iioi~
No. Y
Both Icct~~rc,
fieldwork, sinmlation, disci~ssion.grriclcct cl~scovcry,and
other instnrctional methods can find application in the teaching of
biosplierc. The questions raised abovc which ::tuclcnts sl~oulcl.seek
answers for would servc as target t x 1 3.11~1
~ tll~.oi:gh~lldcpcndentstudy
m c ! group assignments thc pnrpox i!i tcaching ihe unit would bc
achicycd.
srdrnrn3fl{
r
I his u ~ ~has
i t explored the various objectives, contcllts and instructio~~al
activities for teaching the components ol' the environment to secondary
. d ~ o o I students. The details about the application of speciiic
instructional strategies were avoided t o rcctucc rcpctition o r what
appears ovcr flogged in prcvlous wol-ksliop scr-ics.
7