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Clinging in the Kitchen

We often cover our leftover food with a clear plastic wrap. It’s made from a large molecule called vinylidine chloride.

It’s ability to cling to containers depends partly on it’s elasticity. It’s elastic because vinylidine chloride consists of long chains of carbon atoms, which are coiled and kinked like fibres in a piece of wool. When the film is stretched, the molecules straighten out, but, like rubber, they try to return to their original state when released.

As well as being elastic, cling film has an unusual ability to stick to surfaces by electrostatic attraction. --- the same force that encourages dust to stick to your TV screen. As cling film is peeled from the roll, it acquires a static electric charge through friction. You can sense the charge when you hold the film near your face.

The electrostatic charge on the film causes any insulator it touches, like plastic or glass, to acquire an opposite charge. The surfaces then stick together because of the attraction between positive and negative charges. When the container being covered is made of metal, which is a conductor, the plastic film won’t stick. This is because the charge on the film is dissipated through the container, thus cancelling the electrostatic attraction.

So next time you cover leftovers with cling film, remember: use a glass or plastic container if you want the cover to be airtight.

Of all the creatures on earth, humans are among the most prone to save and preserve things for future use. Dogs may bury bones. Squirrels may hide nuts. But humans are constantly saving everything from gold bullion in bank vaults to supper leftovers in refrigerators.

When we attempt to preserve food items, especially those which have already been cooked, we want to maintain them in the best condition possible. That’s where the benefit of cling film comes in. It is able to reduce the risk of potential contamination. It also helps to keep odours and flavours in the refrigerator discrete.

Kitchen leftovers are a tiny proportion of the things we keep. We have different reasons for keeping things. We like to save the things we value. Sometimes their value is intrinsic – gold, diamonds, pieces of art. Sometimes their value is more sentimental – pictures, a newspaper from the day a child was born, a signed book.

The more value we place on an object, the more effort we’ll expend to preserve it. If we want to keep something we treasure safe, we’ll spend a considerable amount to do that, especially if the object itself is unique.

For most of us, the things that we value most are the non-tangible ones. No monetary value can be placed on the relationships which sustain us emotionally, the healthy bodies which allow us to enjoy so many aspects of life, and things like creativity, intellect and emotion, which add passion and perspective to our existence.

It is hard to draw a definitive boundary around the spiritual aspect of our being. Perhaps that is because we are first and foremost spiritual beings with a material aspect. The spiritual dimension is the one that is most important because we believe it endures beyond the life of our physical bodies. No one has found a way of preserving those indefinitely in a useable state! But our spirit is a different issue.

It is worth considering our spirit because that is the part of us that allows us to have a relationship with the divine. That is a privilege of unimaginable proportions. Just think! We have the ability to seek God and find Him.

David Humphreys and Ron Hughes
© August 2004