Rock tumblers are easily available in the market, but are pretty costly. Whether you want to try tumbling some beautiful rocks you found at the beach or are looking for a simple idea for your science project, a homemade rock tumbler will serve the purpose. Also, it is a creative way of making polished stones for adornments. Here are the steps to build a rock tumbler at home. Rock tumblers are instruments that smoothen the surfaces of rocks. Usually, they are manufactured by companies, and use a motor assembly to help rotate the tumbler. In these, you do not have to rotate the tumbler manually, as the motor does the work. The rock tumbler that we discuss here, is a homemade one. It does not use a motor but instead simulates the natural way in which rocks smoothen. This method of building a rock tumbler is quite simple and requires the use of very less equipment. The materials required are easily available at home. ◆ Rocks of your choice ◆ Container ◆ Water ◆ Sand The container used to build the rock tumbler can be one like a coffee tin or any plastic container that is cylindrical in shape and has a tight-fitting lid. Do not use glass containers, as they can break when the rocks tumble. Step #1: Once you have decided the container you will use to build the rock tumbler, fill half of it with sand. This sand will cause the abrasion that will help smoothen the rocks. Initially, use coarse sand. Later, when the rocks start getting smoother, you can use fine sand. Step #2: Now, pour water in the container so that 2/3rd of the container is filled. Mix water and sand thoroughly to form a slurry. This slurry is called grit. Step #3: Put the rocks of your choice in this slurry and cover the container with its lid. Use the same or similar types of rocks in your rock tumbler. Before adding the rocks, identify their type. It is difficult to identify the type after tumbling starts. If the lid is loose, use duct tapes to cover the mouth of the container. Step #4: Your homemade rock tumbler is ready. Once you cover the container with a lid, shake and roll the tumbler in all possible directions. Do this tumbling frequently for several days. The process of rock tumbling begins with rough edged rocks and ends with smooth rocks that have a polished surface. It may take a month or more for the stones to become smooth. A rock tumbler mimics the natural process of stone smoothing, where the stones in rivers and streams tumble due to the action of flowing water. The rocks inside the container are forced to topple on each other and simultaneously mix with the grit. As discussed earlier, use coarse sand in the initial stages of tumbling. As the stones get smoother, replace it with fine sand. The grit used in commercial rock tumblers is usually made from silicon carbide. You can use silicon carbide as grit for better results. The polished stones are decorative and can be used in a number of ways. You can also use them for decorating the base of your fish tank or put them in pots of the plants in your garden. They can also be used to make jewelry items. Building a rock tumbler at home is an easy task and your children can help you too. Homemade rock tumblers make excellent science fair projects, and can be used to explain the geological process of rock tumbling in streams and rivers, to your children. This can be a fun as well as an educational activity for the kids.