Methane (CH4) is the simplest hydrocarbon molecule and the gas that we burn in the lab. It is produced when organic material rots or is fossilised. As natural gas it is one of our three major fossil fuels used to offer a source of energy for power stations such as Didcot B power station. Like all hydrocarbons, methane burns to produce two oxides; carbon dioxide and water.
Methane is also produced by the digestive system of many mammals, especially cows and other ruminants. Ruminants have a complex arrangement of stomachs that allows microbes to break down their diet of grass. The cellulose that forms the cell walls of all plants cannot be digested by any enzymes produced in mammals but can be broken down by some single-celled creatures (bacteria and protista).
One of the by-products of this digestive process is methane. Ruminants are suspected of producing about a fifth of the methane released into the atmosphere annually. This high number is possibly the result of the large herds of cattle needed to supply meat and milk for humans. Methane is a major contributor to global warming because it is even better at trapping the atmospheric heat than carbon dioxide. It doesn’t stay in the atmosphere for long because it tends to slowly oxidise.
We use methane all the time in the lab as it is an excellent, safe source of energy for our experiments. It does release lots of energy when it burns as can be seen in the fun science club experiments in the video below.
Questions…
- What are the main three gases found in air and what are their relative proportions?
- Name a ruminant other than a cow.
- What is the main distinguishing characteristic between bacteria and protista?
- What mineral is supplied by milk and what benefit does it provide?
- Apart from natural gas, what other fossil fuels are there?
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