It’s tempting to think that the litre of gasoline you put in your car is simply burnt, and disappears. Not so. The process of burning gasoline simply strips out all the energy bonds holding different chemical particles together. The bonds in gasoline are particularly strong, hence the energy release is intense – which is the reason it has been so useful for humans. The chemical elements are transformed into gases and small particles with the same weight and mass as the gasoline that was burnt. These particles are difficult to see (and so easily overlooked) and almost impossible to contain once released into the air.

The same applies to liquids that are washed down the sink, or chemicals that are sprayed on the garden, or rubbish buried in the ground. So while we may think we’re throwing things ‘away’ when we put them in the rubbish or anywhere else, the truth is – there is no ‘away’. Nothing disappears.

This principle is captured in the first law of thermodynamics, otherwise known as the principle of conservation of matter. This agreed scientific law recognises the fact that matter cannot be created or destroyed, it can only be transformed from one form to another as its chemical elements are reorganised.