Summary Drop different rocks or minerals into vinegar - carbonate rocks will bubble. Sea shells are made of carbonate and also bubble. Chalk is a carbonate rock and bubbles, showing chemical weathering. Science content Earth/Space: Rock cycle, Earth Materials, Natural resources (5) Science competencies (+ questioning + manipulation + others that are in every activity) Planning/conducting: data collection/recording (K up) Processing/analyzing: classifying data, finding patterns (1 up) Evaluating: inferring (3 up) Lessons activity is in Carbon into shells and rocks Mineral testing Erosion and Weathering by Wind, Water (and Ice) Materials ice cube trays (darker colour shows bubbles best) shell pieces e.g. oyster or clam shells from a beach pieces of calcite, limestone, marble (carbonate rocks) pieces of quartz, quartzite (or other non-carbonate rocks; test first as some carbonate is present in many rocks) vinegar in squeeze bottles flashlights to view bubbles more easily optional worksheet (attached) Procedure Chemical weathering Water can carry chemicals that interact with rocks, change their chemistry, and break them down. Oxygen in the air can chemically react with iron in rocks, making them oxidize (rust!) Rainwater and groundwater absorbs CO2 from the air to make a weak acid, which chemically reacts with rocks. Find out what happens when a weak acid interacts with chalk rock: Add vinegar to a small piece of chalk. Look for bubbles. In the same way, rocks with chalk or similar chemistry will gradually chemically change, which weakens the rock structure and makes it crumble. When CO2 in the atmosphere dissolves in rain water or ground water, it makes a weak acid (carbonic acid). Weak acids chemically react with rocks Carbonate acid test Carbon in the ocean is assimilated into animal shells and rocks. A test for a carbonate-containing shell or rock is the 'acid test'. When a shell or carbonate rock is dropped in vinegar (or other acid), the shell or rock bubbles. Using an ice cube tray to keep tests separate, students can test for carbonate. First add vinegar to a beach shell, and see bubbles streaming off the shell, as it reacts with the acid. These bubbles are from the carbonate in the shell as it chemically reacts with the acid, to make carbon dioxide gas. A flashlight helps to see the tiny bubbles. Students can then be given different kinds of minerals or rocks, some carbonates and some other rock families, to try the acid test on each, and group them into their families (carbonate and other). Use the optional worksheet (attached below). We used carbonate rocks (calcite, limestone and marble) and silica rocks (quartz and quartzite). Note that many rocks contain little seams of calcite (which bubbles), so to find a rock that does not bubble at all these must be absent. Test rocks first. For non-carbonates, we used quartz (easy to find in rock shops) and quartzite (harder to find). Attached documents 3 Carbon into rocks worksheet.pdf Crystal shape carbonate test worksheets.pdf Notes Original worksheet with Uu Updated worksheet with Shaughnessy Grades taught Gr 3 Gr 5 Gr 6
