Procedure

• Partially fill two beakers with the acid.
• Weigh and measure each rock.
• Place them in separate beakers and watch what happens. The limestone will fizz and the non-carbonate rock will not react.
• Check the beakers every 15 minutes. (The dissolving action will stop if either the acid or the calcite is no longer available to react. If this happens, either add more acid or break the limestone to expose more calcite.) In about one hour the limestone sample will be noticeably smaller.
• After drying, the samples can be weighed and measured again to determine the changes.