When opening a tin can, chances are you’ll turn to a can opener or use a ring pull. But these are not the only ways to crack open a tin. In this activity, try using sandpaper to remove the top of a can!
Safety: Open tins can be sharp, ask an adult to supervise this activity. Do not use dented cans.
Canning has been around for more than 200 years. It’s been a great way to preserve food ever since, often keeping it safe for years without refrigeration.
There have been some truly remarkable examples of long-life cans. When the steamboat Bertrand sank in 1865, it was carrying several cans including brandied peaches, oysters, plum tomatoes, honey, and mixed vegetables. Over 100 years later in 1974, chemists tested the food inside and declared it safe to eat!
A can is usually made of three pieces of metal. There are circles for the top and bottom, and a pipe or cylinder to make the sides. To attach the ends to the sides, the two pieces are folded around each other and then welded. When you sand away the top layer, you break the lid away from the folds and weld, allowing it to pop off.
Although they are called tin cans, they are usually made of steel. You can check that yourself with a magnet – magnets don’t stick to tin. They will stick to steel that contains iron!
Steel is a good material for cans because it is cheap, strong and easy to recycle. Over long periods of time it can rust, so many cans are coated in a thin layer of tin. On the inside, cans are often coated in plastic to prevent food acids from dissolving the metal.
Try a different kind of preserving – drying potpourri
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