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Secret Goldenrod Messages
Source Institutions
In this activity, learners write invisible messages on goldenrod paper, and make the message appear and disappear using acids and bases.
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Cave in a Cup
Source Institutions
In this activity (page 2 of PDF under GPS: Cave Swallows Activity), learners will model how caves are formed by placing one piece of chalk in a cup of vinegar and another piece in a cup of water, then