Thursday, May 23, 2013

Practical science

Many people think of science as a remote and difficult subject.  But, actually science is all around us and part of our lives all the time.  I thought I would give some examples that might intrigue you.
When we get up in the morning we have a shower.  We use soap that is caustic so it removes the top layer of the skin.  But, then after the shower we dry ourselves using a towel.  How does a towel work?  It uses surface tension of the water.  Water has an intrinsic pressure that manifests itself at the surface.   If you put a small capillary, such as a straw, into water you will see that the water rises up inside the straw above the level of the water in the glass.  This is surface tension at work in the form of capillary action; the same effect happens in the towel, the surface tension of water causes the water to cling to the narrow spaces within the weave of the towel, and results in a drying effect.
Now you try to dry your hair, but it remains somehow lank and floppy.  This is because, believe it or not, the substance that makes up hair, a structural protein called keratin, has undergone a structural change, called a conformational change, in water.  This was first discovered in the 1930s by William Astbury working at the first research institute devoted to wool and other materials in Leeds, UK.  He took X-ray diffraction patterns of hair and other proteins, both dry and wet, and saw a difference, indicating different structures and he realized that the water was causing a conformational change in the protein. He speculated that the dry form was a bent or helical structure and the wet form was an extended one. Rosalind Franklin did the same experiment in a more sophisticated way in the early 1950s with DNA fibers and showed that there are two forms of DNA. 
So I've given some simple examples of science in everyday life and you are not even dressed yet.


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