Microscope graticules and woolly fringe-moss

 I found the slide graticules for our microscopes. I also viewed my ruler again below to show that the numbers are in millimetres and the smallest scale divisions are 0.1mm.

 I found some moss on the summit of Skiddaw that I hoped was Racomitrium lanuginosum (Woolly Fringe-moss). https://rbg-web2.rbge.org.uk/bbs/activities/mosses/Racomitrium%20lanuginosum.pdf The key feature is the toothed hair point.

Ultra-violet water filter

We found this water filter at Skiddaw House. The frequency of UV is of the order of 10^16 giving a photon energy of the order of 10^-17. Since ionisation energies for carbon, hydrogen and oxygen are 10^-18, the UV can ionise the atoms in living organisms. It can damage the DNA in micro-organisms, killing them. Flow rate needs to be slow enough to allow all the water to be adequately treated but fast enough to stop it overheating. http://filterbutler.com/blog/what-does-a-uv-water-filter-do-and-how-do-they-work/

Skiddaw Metamorphic Aureole 2: Sinen Gill

 Sinen Gill is famous as one of the three places that the underlying Skiddaw Granite reaches the surface. I went looking for the join between the granite and the metamorphosed country rock. I couldn't find the precise place mentioned in the guides but did find the weathered section mentioned.

 I found a large white piece of granite by the stream and there was weathered granite. The rock above, in the picture above, is not granite. I think that is hornfels. So I think this must be where the granite met the country rock. If so, then the temperature 400 million years ago would have been over 1000 degrees Celsius. The metamorphosed rock is brittle in the correct physics definition. It breaks without deformation, but then all rock does. It's just that it breaks into square blocks whereas the original Skiddaw Slate breaks into flat sections along the layers.

Skiddaw Metamorphic Aureole part 1

We went up Mungrisdale Common by way of Sinen Gill. A granite intrusion breaks the surface in the gill and is surrounded by the well-known Skiddaw Metamorphic Aureole. The Skiddaw Slate has been changed by the heat of the magma welling up. This is contact metamorphism. In the distance in this photograph is another gill where we first found evidence of metamorphism. It is about 1km away. I looked up the temperature of magma and perhaps 1000 degrees Celsius would be a ball park figure. I was wondering about modelling the conduction of the heat from the magma through the slate. From https://en.wikipedia.org/wiki/Thermal_conduction heat flux density q=-k.(temperature gradient). So temperature gradient is likely to be of the order of 1 degree Celsius per metre. A value for the thermal conductivity of slate is 2W/mK. Of course, that is roofing slate so it isn't the same thing. But it would give a heat flux density of the order of 2000W per square metre.

A random walk experiment

I have been trying to understand electron diffusion equations in conductors. One is based on a random walk model and gives the probability of finding an electron at a given place at a particular time. It contains a term for the dimension of the space. I was wondering what would happen if I simplified it to one dimension. So I got a coin and tossed it 100 times. I said I was starting from position 0 and moved one to the right for HEADS and one to the left for TAILS. I tossed the coin 100 times. I haven't done that since my introductory maths class on probability in 1978!

I got 52 heads and 48 tails. The position ranged from -2 to 10. Here is a bar graph showing frequency.

It might be heading towards a bell shape. Maybe I would be able to get a Gaussian distribution eventually. I thought I'd been quite smart coming up with this idea but now I've got wifi again I can see that this is a common strategy. This link even computes the probabilities https://en.wikipedia.org/wiki/Random_walk

Sound reflecting from the mountains

Another thing that struck me as the planes went past was that mountains reflect sound quite well. I suppose that should come as no surprise because you can hear echoes but they are usually in tight corries with well defined craggy backwalls. What I noticed was that out on the open fellside, I watched the plane go past, "saw" the sound follow it and then yet there was a distant rumble from behind - the sound of the plane reflecting back from the mountain slopes behind. It's just surprising because it isn't a good reflecting surface. I now teach about diffuse and specular reflection of light. A sheet of paper reflects light but you can't see your face in it because the light is sent in all directions producing a diffuse reflection. That's probably what the mountain is doing to the sound.

Precise snowline in Langdale: rain starts as snow

It had been raining in the valley bottom at night. The very precise snowline around Langdale last week brought home to me that that same rain had been falling as snow half a mile away, and that up the hillside, movement of a few metres must have meant moving from rain into snow. So the conclusion is that all precipitation starts as snow and then melts as it falls. http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/fcst/prcp/rs.rxml Now I'm thinking about the thermodynamics. How quickly can the thermal energy from the warmer air flow into a snowflake and cause a change of state? It clearly isn't an adiabatic process.

Measuring with a microscope

It had never occurred to me before to try to work out a scale of what I am looking at through a microscope. I've only just heard of graticules and don't yet know if we have any. So I measured the size of the illuminated hole in the stage. It was 12mm wide.

Then I viewed the ruler through the microscope. At 4x magnification, that field of view becomes 3mm

At 10x magnification it is just 1mm wide

Also note how wide the scale divisions themselves become!

Scandale Beck hydro

We found this small hydroelectric power scheme. It is said to be the biggest such in Cumbria. https://www.itv.com/news/border/story/2015-10-09/cumbrias-biggest-hydro-electric-scheme-nears-completion/ It cost £2.8million. If 1kWh costs 12p and it generates 2400MWh a year, that would be £288000 a year and so would take 10 years to pay back. I would have thought it would be slightly more than that because some of the 12p will be needed for business running costs.

Wingtip vortices from jet planes

The planes were even closer on Nab Scar. There's one in the picture above just below the skyline on the left. As the planes banked, they produced vapour trails on each wingtip. A vortex is like a tiny whirlpool of air The aerodynamic shape of a wing means that air travels faster above the wing than below and thus has lower pressure above the wing than below. Hence high pressure air can escape sideways around the end of the wing, looping towards the lower pressure above. Meanwhile, the forward motion of the plane drags this looping air forwards into spirals - the wingtip vortices. The spinning air is at very low pressure. It all happens so quickly that there is no time for thermal energy to flow into the vortex from the surrounding air. So that can't be the source of the extra energy to rotate the vortex. The energy has to come from the internal energy of the air in the vortex. This lowers the temperature of the air and water vapour condenses. This is what I could see. https://en.wikipedia.org/wiki/Wingtip_vortices

How fast does a jet fly?

They have been flying jets relentlessly down the Lake District valleys recently. There's one in this picture against the lowest cloud right of centre. We were on Silver Howe above Grasmere and I timed it fly from roughly White Moss Common to roughly Dunmail to try to work out the speed. It took 20 seconds. The distance is maybe 3.5 miles. That's 630 mph. The speed of sound is 767 mph. They mustn't go faster than sound because the sonic boom would break windows.

Solifluction or sheep tracks?

I had always assumed that these small horizontal terraces on hillsides were sheep tracks. I've been reading Derek Ratcliffe's book Lakeland about the natural history of the district and he mentions that a process called SOLIFLUCTION can result in small terraces. He calls it the "frost-sorting of soils and debris". He says that it is due to a freeze-thaw cycle and forms strips of stones with ridges of soil on slopes. He does say it is better on Skiddaw Slates than on Borrowdale Volcanics. This picture above Watendlath is the latter so maybe this is the work of sheep. I now know to look out for solifluction lobes, which don't look like sheep tracks. Sources of pictures that made me wonder are: https://www.alamy.com/stock-photo-possible-example-of-solifluction-soil-fluction-dorset-england-43306329.html and https://www.geograph.ie/photo/475616

Single Pole Double Throw Switch gate in Langdale

This gate on Side Pike in Langdale reminded me of a Single Pole Double Throw switch, otherwise known as a landing light switch. It's the way that the gate pivots in the middle but can close to the left or the right. It just looks like the circuit symbol representation. You can find that here https://learn.sparkfun.com/tutorials/switch-basics/all It's decades since I had to teach it but even when I did, I didn't know that single pole means one single circuit connected but double throw means two "on" positions - hence the landing light.

Static shielding bag for my diodes

I've taught about methods of protection against humans charged with static electricity, and now I've an example in my hands. My synthetic layers often produce sparks and the voltage would exceed the breakdown voltage of the diodes. Hence the bag is conducting. I guess that means that it acts as a Faraday Cage https://en.wikipedia.org/wiki/Faraday_cage I tested the bag with an Ohmmeter expecting to get a low resistance but was off the scale, even on the kOhm settings, so perhaps I've misunderstood. A resistance like that is more like an insulator than a conductor.