Praxis: Making silver shine bright
By Patty Rooks on October 5, 2019.
praxis@praxismh.ca@PraxisMedHat Fall is definitely in the air The mornings have been brisk and even a couple were downright chilly! The trees continue to try and lose their leaves after the early fall blizzard we experienced last week. We all know that as fall arrives, so does Thanksgiving! What a wonderful time of the year. I hope that each and every one of you takes a moment and be thankful for what you have and those you are able to share it with. Often times we are so busy we forget to be thankful, especially for the little things. As we prepare for a large festive gathering, some of us may be pulling out that silverware that has been sitting in the drawer for a little while. Oh dear, it may need a polishing. But why does it need to be polished is a question I will likely have to answer in my household. Well, it all comes down to science so we had better investigate this a bit more. Let’s get started! *Remember to ask an adult before doing this experiment. Materials – several pieces of dirty silver – large glass bowl – aluminum foil – kettle – baking soda – water – measuring cups Procedure 1. Using the aluminum foil, line the inside of the glass bowl. 2. Place the pieces of sliver you would like to clean in the bottom of the bowl on top of the aluminum foil. It is very important that the silver touches the aluminum foil. 3. Have an adult help you fill and boil the kettle with water. 4. Measure 1 L (4 cups) of boiling water and pour it into the bowl. 5. Add 125 mL (1/2 cup) of baking soda slowly to the bowl. Be careful as it may foam and froth up, you do not want to get burned by the hot water. 6. Allow the silver to sit fully submerged in the water/baking soda mixture for about 15 minutes. 7. Remove and polish with a soft dry towel. What is going on? You have probably noticed that each time you pull out those beautiful pieces of silver from the cupboard they are all black or stained. Perhaps you also have some jewelry that has black on it. It is probably silver as well. Well, silver is usually a bright shiny metal but it becomes stained or tarnished when it reacts with the sulfur in the air causing those black spots or silver sulfide you probably see. In this experiment you caused a chemical reaction to change the silver sulfide back to silver. It all started when the silver started touching the aluminum foil. The sulfur atoms moved from the silver pieces to the aluminum foil. This frees the silver metal and now makes aluminum sulfide. A chemical reaction takes place when they are both in the baking soda solution. The baking soda solution carries the sulfur from the silver to the aluminum. The aluminum sulfide is able to stick to the aluminum foil and away from those beautiful pieces of silver now. Do not forget that the silver and aluminum must be touching one another for the reaction to occur because there is actually a small electrical current flowing between them, or an electrochemical reaction. Who knew it was such a complicated process just to get beautiful sparkling forks and knives and jewelry?!! Teachers please do not forget to book your Hands-on Learning Kits, Scientists in the Classroom presentations and Science Fair 101 Program as soon as possible. Spots are filling up fast! Patty Rooks, Senior Scientific Consultant PRAXIS, “Connecting Science To The Community.” Contact Praxis at praxis@praxismh.ca, http://www.praxismh.ca, Tweet or follow us @PraxisMedHat, or friend us on Facebook. NOTE our NEW address: #12 826 11 Street S. E., Medicine Hat, Alberta, T1A 1T7 Phone: 403-527-5365, email: praxis@praxismh.ca. 25-24
