More Than Living

What is this carbon dioxide stuff anyway?

While writ­ing our earlier Lotus post, it occurred to us that every­body does a lot of talk­ing about carbon diox­ide, without ever really remind­ing us what the stuff is. So, for anyone who was having a quiet doze during school chem­istry les­sons, here’s a quick refresher.

Carbon diox­ide is a col­our­less, odour­less gas that’s present in the air we breathe, although it makes up just a tiny frac­tion of it. There’s rather more of it dis­solved into a fizzy drink – it’s what unruly chil­dren burp up if they drink too much pop.

Most organic matter (and the fuels derived from it) con­tains large quant­it­ies of carbon, and when it burns this gets com­bined with oxygen to pro­duce a lot of CO2. The gas’ moniker comes from the fact that each of its molecules is made up from one carbon © atom, bonded to two oxygen (O) atoms. It’s not to be con­fused with toxic carbon monox­ide which is pro­duced when there’s not enough oxygen around – its molecules con­tain only one oxygen atom.

Carbon diox­ide is also released as waste when living things extract energy from their food, which is why we breath the stuff out in higher con­cen­tra­tions than we breath it in. With so many of us belch­ing it out, levels would quickly build up, but plants use the gas as a build­ing block for the sugars they pro­duce during pho­to­syn­thesis, remov­ing it from the atmo­sphere almost as quickly as it’s produced.

Still with us?

CO2 also has a couple of unusual prop­er­ties. Unlike most other gases, it’s never found as a liquid at normal pres­sures. Dry ice – beloved back­drop to 80s photo shoots – is frozen carbon diox­ide. The groovy vapour is pro­duced as it heats up and turns dir­ectly into a gas – a pro­cess known as sublimation.

In the atmo­sphere it’s also a green­house gas; absorb­ing heat from the sun that bounces back off the earth’s sur­face, and reflect­ing some of it back down­wards. Without this effect, the earth would be too cool for us to live on, but CO2 levels have increased markedly since the indus­trial revolu­tion, increas­ing the amount of heat that gets trapped by the atmo­sphere – it’s one of the main factors thought to cause global warming.

IMAGES

While look­ing for pic­tures to illus­trate this post, we happened on these amaz­ing shots by Flickr user jur­vet­son. They’re pic­tures of an art-​​come-​​science exhibit by Shawn Lani that pitched chips of dry ice into a bowl of water. There’s some stun­ning video of Icy Bodies on the Shawn Lani Stu­dios website.

Sim­ilar Posts:

• New research shows link between cleaner air and rise in temperature
• What is carbon labelling?Counting carbon diox­ide emis­sions to change lifestyles
• Bio­fuels compared
• Top ten tips to cut down on cent­ral heating use
• Why Living is involved in Blog Action Day — and you should be too

Ori­gin­ally posted 2008-​​03-​​20 11:02:00. Repub­lished by Blog Post Promoter

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