I am interested in the simplest scientific experiment that a layman can carry out in order to determine rough measures regarding the Earth's shape and size. Think high-school education or less, if possible
Can't you just google it? This is a debate forum for issues dealing with Evolution V Creation. Not a forum for high school science experiments.
Look around on the site to see what people are discussing and come back a while later after you've involved yourself with some of the debates.
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