The view from Howth pier last week.
Most people will say that the wind is blowing to the right in this picture without even thinking about it, because leaves don’t get blown onto trees. That’s because of the 2nd law of thermodynamics, which is something that almost nobody can explain to another person, but almost everybody understands intuitively thanks to things like this we see every day.
Apatite is the mineral found in our teeth and bones, but it also comes in hundreds of other forms and is found in many types of rock. It gets its name from the Greek for “deceive”, because it is sometimes so difficult to tell what type of apatite you are looking at, or even if it is apatite at all. For example, what you are looking at right now is part of an x-ray diffraction pattern for fluorapatite, but it looks more like some mountains and trees.
This week I couldn’t decide whether to do a landscape or continue the diffraction theme, so I did both! Any time a wave meets an object about the same length as it, it gets diffracted and changes direction, and more objects means more diffraction. So in theory**, if you have a big farm and set your fields up carefully, you can do some serious messing with your neighbours radio reception. That particular example might not seem very helpful, but the same idea is used in all kinds of measurement systems, such as the electron diffraction in crystals from last week.
**Science tip: never trust a sentence that starts with “In theory”.
Take some electrons, accelerate them at 200,000 Volts, bend them into a tiny beam with electromagnets, fire them through some crystals, bend them again with some more electromagnets…and we see diffraction.
A slightly easier way is to look at the back of a CD, where the tiny lines on the CD diffract light and separate the different colours. Replace ‘light’ with ‘electrons’, and ‘tiny lines’ with ‘rows of atoms’ and we get an electron diffraction pattern that tells us a lot about nano-sized and even smaller structures, and gives a kind of fingerprint for each material. It’s worth the extra hassle, and some of the patterns can be quite beautiful too!
Perhaps not as famous as the double helix of DNA, the triple helix is just as useful and 50% more helical. It is the structure of the collagen molecules that make up a big part of our bones, teeth, muscles, skin, and various other bits. The triple helix shape helps to make it strong and tough, a bit like the twisted fibres of a rope.
More importantly, the triple helix is the path followed by the feathers on an arrow, so when my archery coach says “visualise the arrow hitting the middle of the target” I see something like this.
A form of wet precipitation more familiar to most people than “Wet Precipitation 1”, though it’s usually pronounced “rain”. That greenish blue under a big rain cloud is probably the best colour anywhere, which is why I’m one of the few people happy to see a forecast for thunderstorms. Also, this makes it three paintings in a row from right outside the front door…there’s always something new to see if you look up.