Science Smarts: Let’s get polished

By Patty Rooks on October 11, 2025.

I know I promised to keep up with the Halloween experiments but I have had a special request to do a useful experiment for Thanksgiving. This weekend, many will be gathering to celebrate the holiday and with that comes using your very best place settings. If you are like me, when you pull anything silver (even jewelry) out it has this black “stuff all over it, not to mention it just does not shine anymore. Well, with a little bit of science, I can help you make that silver shine again. Let’s get started!

*Remember to ask an adult before doing this experiment.

Materials

– Several pieces of dirty silver (jewelry OR silverware)

– 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 silver 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. You need to make sure to spread it out if you are using jewelry.

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 sulphur in the air causing those black spots or silver sulphide you so desperately want to get rid of.

In this experiment you caused a chemical reaction to change the silver sulphide back to silver. It all started when the silver started touching the aluminum foil. The sulphur atoms moved from the silver pieces to the aluminum foil. This frees the silver metal and now makes aluminum sulphide. A chemical reaction takes place when they are both in the baking soda solution. The baking soda solution carries the sulphur from the silver to the aluminum. The aluminum sulphide 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 or your precious jewelry?!!

Mark your calendars, our annual FAMILY SCIENCE OLYMPICS will be on Saturday, Oct. 18 from 10 a.m. to 3 p.m. This is a FREE event BUT one adult must accompany all participants. I am looking forward to seeing you there!

Patty Rooks, senior scientific consultant Praxis Science Outreach Society. Praxis has moved! We are very fortunate to be located in the Community Futures Enter Corp Building at #202 556 Fourth St. SE, Medicine Hat, Alberta, T1A 0K8. For all your science needs, please email prophylaxis

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