Kerry McKay takes a look at the properties that make water the supporter of life , and the prospect of microplastics altering our planet ’ s sustenance
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ENVIRONMENT
Wondrous water
Kerry McKay takes a look at the properties that make water the supporter of life , and the prospect of microplastics altering our planet ’ s sustenance
Water is one of the most amazing substances in the universe . All life relies on water to exist , and for many of us , water brings a quality of life to our often stressful lives . World Water Day is on the 22nd of March , so let ’ s take a moment to appreciate the wonders of H2O .
Water is a small and simple molecule composed of one oxygen atom and two hydrogen atoms . The hydrogen atoms are not directly opposite each other , making water an unbalanced molecule . This is what makes water polar , meaning it has a slightly positively charged side ( the hydrogen atoms ) and a slightly negatively charged side ( the oxygen ). From this simple structure stems all of water ’ s amazing properties .
Having charged sides means water molecules stick to themselves ( cohesion ). This is what causes water to have surface tension . You might best remember this property from a painful belly-flop at the pool ! This cohesion is also why trees can suck water upwards , against gravity .
Water can dissolve other polar substances , such as the salts and nutrients that make the sea salty . Think of magnets attracting each other . In contrast , oil is a non-polar substance that has no charge . This is why oil doesn ’ t mix with water .
Unusually , water can be found naturally in liquid , solid and gaseous states . Even more remarkably , solid water ( ice ) floats on liquid water . The crystalline structure formed in ice crystals holds the molecules apart . In liquid water , the molecules rub close around each other making the liquid more dense . This is handy as it means ice forms on the water ’ s surface , leaving the depths as a liquid for life to go on living , and of course , for us to go ice diving .
It takes lots of energy to increase the temperature of water , known as a high heat capacity . This is useful in the environment , as it means that bodies of water can absorb lots of energy before they get warmer . This helps to regulate temperature , keeping it more stable for the awesome things living in water .
The high heat capacity of water also makes it good at heat exchange . This is important for all living cells to function , as well as for certain technologies such as the steam engines we see in shipwrecks .
Studies suggest the oceans have absorbed over 90 % of global warming so far , but we know the oceans are now warming .
The sun is a strong energy source and can turn water into a gas . Cloud formation is usually triggered by tiny particles , such as dust , acting as cloud condensation nuclei . Massive volcanic eruptions spewing dust into the atmosphere can lead to more cloud formation and a global cooling effect . Now scientists are learning that microplastics ( plastic particles less than 5mm in size ) are even in our air , and are also likely to lead to more cloud formation .
Plastic particles in the upper atmosphere degrade much faster than on the ground due to the increased exposure to UV radiation . This means more microplastic particles are being created in our skies as larger pieces break apart . As they degrade , these plastics release greenhouse gases , contributing to global warming , and more particles to trigger cloud formation . Of course , if there is plastic in our clouds , then it should be no surprise that there is plastic in our rain too .
Atmospheric and ocean circulation causes microplastics to be concentrated in the polar regions . This has happened repeatedly with many pollutants and harmful xxxxxxxxxxxxxxxxxxxxxxx
chemicals , such as heavy metals and persistent organic pollutants . The cold regions trap these substances , essentially holding them in cold storage . As the polar regions warm up and ice melts , we could face a large release of centuries worth of pollutants into our environment .
We live in the ‘ plasticene ’ and there are consequences for our careless actions . If you haven ’ t already started finding ways to reduce plastic in your life , there ’ s no better time than now . �
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