It takes a long time for a cenote to form.
Rain water absorbs a gas (carbon dioxide) from the air and forms a weak acid. As this trickles down through tiny cracks in the limestone, the weak acid dissolves a mineral in the limestone called calcite. Over time the limestone is dissolved and a cenote is formed.
Put three drops of water on the chalk. - What happens?
Put three drops of vinegar on the chalk. - What happens?
Chalk is made from limestone. Vinegar is a weak acid.
Try other liquids.- Did you find weak acids?
Number your rocks and print the logbook sheet.
Compare these rocks to the limestone. - Record your results.