First posted 18 Feb 2012
Humans are grubby. We sweat, shed skin cells, and collect soil, dust and general grime at an alarmingly rapid rate. Anyone with children will understand that although adults are pretty messy, children seem to be fine tuned to make and attract grime.
Having lived without a washing machine for a couple of months I now fully understand the chore of washing clothes, and how grubby everything gets. Hand washing turns out to be very labour intensive and in our hectic modern lives isn’t a particularly efficient use of time.
It is estimated that the average American family does on average 300 loads of washing a year (Source: Wall Street Journal). In each and every load they use detergent. This fact set me thinking as to how detergents work and what we used before we had the washing machine and detergent technology of today.
A detergent is a chemical substance used to break up and remove grease and grime, it allows oil and water to mix removing oily grime from the fabric.
Soap is one solid type of detergent, in general they are liquids or powders/solids. Hair shampoo, clothes powder, shaving foam and stain removers are some of the common detergents that we use regularly.
Most modern detergents are like soaps, but are less likely to form a scum and are not as affected by minerals in the water. Useful if you live in a hard water area. Soap foams less in these areas, and so you need to use more. You’ll probably have noticed that the back of the packet f clothes detergent tells you to use different amounts for different water.
Funnily enough the topic of detergents it is mildly related to last weeks 1000 words, as detergent acts to reduce the surface tension of water.
Detergents contain surfactants, a word formed from the words Surface Active Agents. Modern detergents for clothes also contain enzymes, bleaches and blue dyes. Surfactants are produced from petrochemicals and they work by lowering the surface tension of water. Essentially making the water less likely to form droplets and therefore it feels wetter.
Also included in modern detergents are enzymes, to break dirt down, proteases break down proteins, lipase break up fats and amylases break down starch. Perfumes are a common addition and some of the more forceful household cleaners include abrasive substances.
The main action for dirt removal is down to the surfactants, molecules which are hydrophobic at one end and hydrophilic at the opposite end.
The hydrophobic, meaning water hating, end of the molecule sticks to the grime, essentially to get “away” from the water. The other end of molecule is hydrophilic, and thus loves water and is attracted to the water. Although this is clever and interesting, this molecule is not enough to clean the dirt from the garment. In addition, you need to agitate or use mechanical energy to mix the soapy water around allowing the detergent to pull dirt from the fabrics into the of water.
Soaps have been in existence for a very long time. The first evidence for soap production and use is by the Phoenicians in the Mediterranean in 600 BC, but up until around 1790 AD soap was an expensive luxury, until the French chemist Nicholas LeBlanc finds a cheaper way of making soap using salt.
Soap was originally made with animal or vegetable fats and surfactants were developed as a response to the shortage of these fats after WWI and WWII.
Surfactants were invented during the First World War in 1916 by the German chemist Franz Gunther. They were made from coal tar, which is not something that you would naturally associate with getting things clean. This invention leads to surfactants being used in detergents to great effect, and in the 1930s the technology of surfactants are introduced in the USA.
In the 1950s synthetic detergents are developed and soon overtook the traditional animal or vegetable fat soap. Another invention also becomes more affordable and common at this time, the automated washing machine. Further changing and improving how we got our clothes clean.
Before washing machines all washing was done by hand. There were some labour saving devices, but even these were relatively recent inventions. For instance the mangle, and the wash board were only invented in the last 200 years. Before this we used stones to agitate and bash the dirt out.
Garments were hung things out to dry on trees and I imagine humans were an odorous species right up until the very recent past. Even now only developed countries have access to luxuries such as washing machines and detergents that work on all kinds of stains.
Also vaguely related to the theme of washing and detergents it was recently reported on the BBC website a story about a rare lizard from the Cape Verde Islands not only surviving a 3000 mile flight to the UK, but also living through a machine wash. The traveller inadvertantly packed him up and he travelled all the way to the UK, he was then thoroughly washed and spun dry before being noticed. She admitted screaming in surprise on her discovery, but quickly became fond of her little hitch hiker.
It seems the Chioninia Lizard was no worse off from the experience, and is perhaps a little cleaner? He has been named Larry and has been rehomed at Tropiquaria Wildlife Park in Watchet. There are concerns that the washing powder detergent could have been inhaled by the lizard, which could affect its lungs and could cause pneumonia but so far Larry is showing no signs of ill health. Get well soon Larry!
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