Penny cleaning science tej yaam num yog ib qho kev xaiv nrov ntawm cov tsev kawm ntawv qib siab science fairs - thiab yog vim li cas. Cov chemistry qab qhov kev sim yog qhov yooj yim tab sis nthuav, thiab qhov project yog ib qho yooj yim rau cov me nyuam ntawm txhua lub hnub nyoog ua. Tus kws tshawb fawb hluas sim nrhiav seb qhov twg ntawm ntau qhov kev daws teeb meem yuav ntxuav cov pennies zoo tshaj plaws, tshem tawm cov tooj liab oxide uas ua rau lub ntsej muag du thiab tarnished.
Setting Up the Project
Pib, tus kws sim thiab saib xyuas cov neeg laus yuav tsum npaj cov kev daws teeb meem uas lawv muaj peev xwm nkag mus thiab siv tau los sim lawv cov peev txheej tu nyiaj. Lawv yuav xav tau ib lub tarnished, qias neeg-saib nyiaj rau txhua qhov kev daws teeb meem xaiv ntxiv rau ib qho ntxiv raws li kev tswj hwm (txhais tau tias tsis muaj dab tsi yuav ua rau qhov nyiaj kawg no). Nrhiav pennies ua ntej 1982 thiab kwv yees li tib lub sijhawm; ua li no lawv yuav tarnished ntau thiab cov pennies yuav muaj xws li.
Ntxhais kev daws teeb meem
Thaum tus kws tshawb fawb budding muaj ib pawg pennies, nws yuav tsum xaiv thiab sau lawv cov kev xaiv ntawm kev ntxuav. Feem ntau ntawm cov no tsis yog cov khoom uas feem ntau siv los ntxuav, uas yog ib feem ntawm kev twv seb lawv yuav cuam tshuam li cas rau pennies lom zem dua.
Qee cov lus qhia muaj xws li:
- Plain dej
- Zoo dej
- Lemon kua txiv
- Vinegar
- Vinegar nrog ntsev
- Ketchup
- Hot sauce
- Coca Cola
- Baking soda thiab dej
- Apple, grape, or orange juice
- Muaj
Forming ib Hypothesis
Ib qho kev xav yog kev kwv yees ntawm qhov yuav tshwm sim hauv qhov kev sim raws li kev paub uas tus kws sim twb muaj lawm. Hauv qhov no, tham nrog tus kws tshawb fawb hluas txog cov kev daws teeb meem uas nws xav tias yuav ntxuav cov pennies zoo tshaj plaws. Lawv kuj tuaj yeem xav txog qhov twg yuav ntxuav cov pennies sai tshaj plaws. Cov menyuam yaus feem ntau xav tias cov dej xab npum yuav ua haujlwm zoo tshaj plaws vim nws ib txwm siv los ntxuav, tab sis cov menyuam yaus uas nkag siab tias cov kua qaub yog dab tsi lossis leej twg paub me ntsis txog chemistry tej zaum yuav muaj lub tswv yim zoo txog qhov yuav ua haujlwm.
Performing the Experiment
Qhov kev sim no tuaj yeem ua nrog cov khoom uas feem ntau pom nyob ib puag ncig lub tsev, yog li nws yog qhov kev xaiv zoo rau txawm tias qhov project nag los nag. Ib qho kev xaiv yog suav nrog kev siv cov ntawv pH (uas ntsuas qhov yooj yim lossis acidic ib yam dab tsi thaum daim ntawv dipped rau hauv ib yam khoom) los pab tus menyuam kom nkag siab tias vim li cas qee qhov kev daws teeb meem yuav ua haujlwm zoo dua li lwm tus. Qhov kev sim ua tiav nrog kev lom zem thiab kawm ntau yam tsis siv lub cuab yeej no.
khoom siv
Thaum muaj qhov kev xav ua haujlwm, qhov kev sim nws tus kheej tuaj yeem pib. Nov yog yam uas tus kws tshawb fawb hluas yuav tau pib:
- Tsawg kawg yog ob qhov kev daws teeb meem los ntawm cov npe saum toj no
- Pib nyiaj rau txhua qhov kev daws teeb meem ntxiv rau ib qho ntxiv
- Ib lub tais me me los yog khob rau txhua qhov kev daws teeb meem (cov khob yas los yog ntawv nrog ob peb nti tawm sab saum toj txiav tawm yuav ua haujlwm yog tias tsis haus iav kom tsis txhob muaj)
- Masking daim kab xev (yeem)
- A marker
- Tweezers
- pH ntawv (yeem)
- paper phuam
- Camera (yeem)
Directions
Txhawm rau ua qhov kev sim yooj yim no, ua cov hauv qab no:
- Siv daim kab xev thiab cim, sau txhua lub tais lossis khob nrog lub npe ntawm cov tshuaj uas yuav nkag mus rau hauv.
- Pho kom txaus ntawm txhua qhov kev daws rau hauv nws cov tais sib xyaw kom npog cov pennies (nws tsis siv ntau).
- (xaiv tau) Muab ib daim ntawv pH hauv txhua qhov kev daws (nws hloov xim xiav ntau dua rau cov kua nruab nrab thiab ntau xim liab rau cov kua qaub), cia nws qhuav, thiab sau cov kua uas nws tau dipped rau hauv.
- Muab ib lub nyiaj tso rau hauv txhua lub kua thiab xyuas kom meej tias nws nkag mus rau hauv dej.
- Cia zaum 10 feeb.
- Cia li muab cov pennies tawm ib zaug thiab, cia li taug qab seb lub penny yog tus twg, yaug txhua tus tawm.
- Cia cov pennies qhuav ntawm daim ntawv phuam.
- Sau koj cov txiaj ntsig; cov duab yog pab tau.
Sib tham txog qhov tshwm sim
Thaum cov qhabnias nyob rau hauv, tham nrog tus menyuam txog qhov twg pennies zoo huv si thiab yog tias lawv tuaj yeem pom cov qauv hais txog cov kev daws teeb meem zoo li ua tau haujlwm zoo tshaj. Qhov no yog ib qho laj thawj uas cov ntaub ntawv pH tuaj yeem yog cov cuab yeej pab tau.
Kev nkag siab kev nyuaj siab
Lo lus "tarnish" yog hais txog cov xim dub lossis grey-ntsuab uas pom ntawm qee cov pennies qub. Nws tsis yog av xwb, nws yog qhov tshwm sim ntawm cov tooj liab hauv cov pennies cuam tshuam nrog oxygen hauv qhov chaw. Thaum cov pa oxygen thiab tooj liab ntawm cov npib sab nraud cuam tshuam, ib yam khoom hu ua tooj liab oxide yog tsim. Txhawm rau tshem tawm cov tarnish no, cov kua qaub yuav tsum tau siv los ua kom tsis muaj zog ntawm cov tooj liab thiab oxygen atoms. Ntxiv ntsev rau ib qho ntawm cov kua qaub (cov kua txiv qaub, kua txiv qaub, thiab lwm yam) ua rau cov kua qaub no ua kom zoo dua los ntawm kev tsim cov hydrogen atoms dawb hauv cov tshuaj, uas ua rau cov kua qaub ua kom muaj zog.
The Results
Yog hais tias qhov kev sim no yog siv rau kev tshawb fawb ncaj ncees lossis kev nthuav qhia hauv chav kawm, tus kws tshawb fawb hluas muaj kev xaiv los thaij duab ntawm txhua lub nyiaj npib nrog rau daim ntawv lo rau cov tshuaj uas tau siv lossis txawm coj cov pennies lawv tus kheej hauv. tus me nyuam yuav txiav txim siab xaiv ib qho kev daws teeb meem los sis txawm muab cov nyiaj pennies nyob rau hauv kev txiav txim uas yog qhov zoo tshaj plaws. Tus me nyuam yuav tsum tau npaj los tham txog vim li cas lawv xav tias qee qhov kev daws teeb meem zoo dua li lwm tus.
