RETK KOOBASTES

     Vesi õõnestab mägesid ka seestpoolt. Nii tekivad koopad.
     Koobasteks nimetatakse kivimiõõnsusi, mis on küllalt suured, et inimene saaks neis liikuda.

     Enamik koopaid asub lubjakivis, kuid neid on ka liivakivis ja graniidis.
     Suurimad koobastikud on tekkinud põhjavee toimel.

     Kui vesi imbub läbi kivimite, lahustuvad selles mineraalained ning maa alla tekivad tühikud ja õõnsused - karstikoopad.
     Karstikoopaid on ka Eesti paeses pinnases.

     Mineraale sisaldav vesi loob koobastes kummalisi ja imepäraseid kujundeid - laest rippuvaid kivipurikaid, põrandast “kasvavaid” seeni ja torne.

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1. Kas sinu kodukohas leidub koopaid?
Uuri järele ja kirjuta, mida tead oma kodukandi suurimast koopast.
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2. Kirjuta, kuidas on tekkinud stalaktiidid ja stalagmiidid!

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Stalaktiidid.................................................
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Stalagmiidid..................................................
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