Just finished a set of three books by New Scientist magazine assembled from a column devoted to reader questions along with a selection of reader replies (the first title in the series is the title of this post.) The appeal of the questions and quality of the answers varied a great deal, but I learnt a few interesting points which I’ll attempt to abridge below:
The amount of water in a cloud is not different than the clear air around it, its only a temperature difference which has caused the water to condense into droplets and become visible.
I’ve never tried photochromic lenses but apparently they are temperature dependent and work poorly in warm weather, which somewhat defeats the purpose unless you are skiing.
Aluminium is much more reactive than we usually think because it quickly forms a protective oxide layer. Mercury can disrupt this, and then spread like wood rot, hence is banned on planes.
I also found some of the biological explanations interesting, mostly because I know embarrassingly little about this subject:
About a quarter of humans have a tendency to sneeze when going into bright sunlight. Its called a photic sneeze and happens because the protective reflexes of eyes and nose are closely linked. It is a well known hazard for combat pilots but was noted as early as the 17th century by Francis Bacon.
We don’t normally notice the Purkinje shadows which appear on the retina caused by the light having to pass through blood vessels and fibres (unlike a squid’s eye) because we are not good at registering stationary images. We only see stationary objects because are eyes are constantly jiggling about. If we undo this using eye-tracking technology, we can make objects disappear – Troxlers’s fading. We can only see the aforementioned shadows if we vary the angle of the light entering the eye via a pinhole in a card or shining light into the white part of the eye.
There is a physical section of the brain devoted to signals from different parts of the body called the somatosensory homunculus and fingers, for example, get much more brain to talk to than say the back.
The flu virus can live on a cash note for up to 17 days.
When a platelet (part of the bloodstream) encounters a wound it activates its integrins (surface receptors) enabling it to glue itself to the fibrinogen in the blood vessel. The non-cellular tissue in the body (the extracellular matrix – teeth, cornea, tendons etc.) is mainly produced by localised fibroblasts using fibre forming proteins: collagens and elastin (structural) or fibronectin and laminin (adhesive)
However in that last example I’m not really sure I learnt anything other than there were names for interesting things. The prospect of me being able to performing any calculations seems unlikely – I’m guessing protein dynamics isn’t the sort of subject you can dabble in. Maybe thats why I prefer basic physics: at least you get to play with the equations.