Granophyre and the Carrock Fell hill fort

After posting about granophyre, I then read that the hill fort on the summit of Carrock Fell is made of granophyre boulders, according to my geology walks book. Here is a glorious example, the pink of the rock enhanced by sunset.  I looked up the GCR sheet on the subject and found this http://jncc.defra.gov.uk/pdf/gcrdb/GCRsiteaccount295.pdf  This document calls it "microgranite". I am still trying to find out if microgranite is another name for granophyre. Microgranite would imply smaller crystals so faster cooling which would occur closer to the surface. I climbed up to the summit cairn unsure of where the wall of the fort lay.

There I looked back and saw the gateway below and the tumbled down ramparts. The rock photographed was actually part of the wall! I'd climbed over it.

Crummock Aureole at Bowness Knott

I collected the rocks on the right from the summit of Great Borne in Ennerdale. They are made of Ennerdale Granophyre. Granophyre is an intrusive rock with a similar composition to granite (hence the pick colour) but is said to be "subvolcanic" rather than "plutonic" meaning that it crystallised closer to the surface - at depths of less than 2km. This means it would have cooled faster than deeper rock, I think. It gets hotter as you go deeper so that would make sense. Hence the crystals are smaller. As we came out of Rake Beck and down towards Bowness Knott, I found a very different rock, shown left. It seems much harder with no obvious crystals. It occured to me that an intrusion ought to have a metamorphic aureole, and that the rock I found was likely to be a hornfels. And then I found this which confirms what I thought http://jncc.defra.gov.uk/pdf/gcrdb/GCRsiteaccount296.pdf
Here's the granophyre on the summit

And here is Rake Beck which seems to be the boundary of the aureole

Physic isn't Physics

 This advertisement was up outside the Botanic Garden in Oxford. The name of my subject Physics comes from Greek. The original word meant "natural things" because we study things that are not human inventions like art or literature. It seems to have become focused on non-living things though. So it is not unreasonable that growing plants should have a word from the same origin. A Physic Garden was where medical plants were grown. https://en.wikipedia.org/wiki/Physic_garden I was expecting it to be derived from physical, as in to do with bodies, but it seems physical has developed in parallel with Physics as a word.

Wonderful planetanimation

This was on APOD yesterday https://apod.nasa.gov/apod/ap190520.html It is very easy to take in the information. I knew that Uranus lay on its side but was amazed by how fast Jupiter rotates. Also noted that Venus is rotating in the opposite direction to the rest and very slowly.

Clubmoss and Physics experiments

I found Fir Clubmoss on the fells as shown above. I had to look it up and found that there is another rarer type called Alpine Clubmoss which is Lycopodium fastigiatum. I use lycopodium powder in Physics and was interested to find out that the powder is the dry spores of such plants. I have used it in an experiment to try to measure the size of an atom. You sprinkle lycopodium powder onto the surface of water and then add an oil drop, having first measured the diameter of the drop to enable the volume to be calculated. The oil slick is then said to have a very flattened cylindrical shape but with the same volume. If you assume the slick is only a few molecules thick, by measuring the diameter and equating the volumes, you get a ball park figure for molecule size. I've never got it to work because the oil slick has never been a decent circle.

Life of Pye

Pi has so many uses in the mathematics of Physics. At the moment I am dealing with a lot of Quantum Mechanics and so come across h-bar a lot. That is Planck's constant divided by 2pi. I have found out that this should really be called the reduced Planck constant and that it was introduced by Bohr whilst he was trying to come up with the quantum for the angular momentum of an electron https://en.wikipedia.org/wiki/Planck_constant I had assumed that it came from the conversion from frequency f to angular frequency w where w=2(pi)f.

Thermoelectric generator fan at Skiddaw House

I have seen these fans in a couple of places and have now found out a bit more about how they work. They have no battery - just a metal base made of two different types of metal. This acts like a thermocouple. Thermal conduction results in movement of charge carriers, concentrating them in one place and resulting in a potential difference. https://en.wikipedia.org/wiki/Thermoelectric_generator I notice that it is best when high electrical conductivity is coupled with low thermal conductivity. It seems to be the reversal of the Peltier effect, where running current through a two metal junction results in heating or cooling.

Dispersion of waves ruins my required practical

We measured the speed of waves on water by lifting and dropping one end of a tray and timing the movement of a wave along the water. The wave was moving at around 30 cm/s. We then set a dripping tap to create waves of a particular frequency. This was of the order of 1 Hz. By the equation wave velocity = frequency x wavelength, the wavelength should be of the order of 30 cm. Look at the picture: That certainly doesn't seem to be the case. The problem appears to be that the equation might not apply in this example. Such waves are called capillary waves https://en.wikipedia.org/wiki/Capillary_wave The data about the waves given in the article seems to tie in. A dispersion relation is given which will need investigating but I need to work out how to calculate the surface tension.

Force-extension graph for wool

 It is traditional to use copper wire to explore the force-extension graph for solid materials. The problem is that using the masses that we have, it is very hard to got any results. So I decided to take up the suggestion of using wool. I added 10 gram masses in intervals up to 150 grams.

 I used a set square to avoid parallax error and my rather scrunched up graph is below. I'm going to try this with my class next week because the results being different in loading and unloading is an interesting feature. The problem is the lack of straight section which will make the calculation of the spring constant tricky.

Measuring the rain behind Skiddaw

We were pinned down by a 20 minute shower in the Skiddaw Forest. I was musing about the white noise of the random raindrop pattern on the membrane of the umbrella and then took to measuring the drop rate from the corners. I was able to count 20 drops in 15 seconds. Then the rain eased and there were 12 drops in 15 seconds. Then the rain came on heavier again so that it was impossible to count the drops. I'm wondering about trying to work out how to calibrate the drop rate to measure the strength of the rain.

Motor effect demonstration

I like this old demonstration using kitchen foil. Aluminium is not a magnetic metal but turn on the current and watch the foil be repelled from between the magnets. It's the electric current that is affected by the magnet. Either swap the magnet round or change the direction of the current to make the foil move in the opposite direction.

Why the snow wasn't melting on Gable

 I was the last snow of the winter on Great Gable today (well, at least I hope so)

 The flakes landing on the path melted within seconds. Rock might be "stone cold" but it must have been higher than 0 Celsius and thus conducted into the snow to melt it. Rock is "stone cold" because it is quite a good conductor of heat so it takes heat out of your hand, leaving it feeling cold to the touch. Here, the conduction ability means thermal energy flows well into the snow.

 On the grass, the snow lingered. I'm guessing that's because as it lands, most of the flake is still suspended in air and the air is a much better insulator than the rock.

Solar System mug

 I have been given a Solar System mug. Can you spot what is wrong with the Earth?

I also liked that it still had Pluto on it. I appreciate that it was demoted from full planet status because of the number of similar sized objects that have now been found on the fringe of the Solar System but for old times sake, it's nice to have what I grew up with.

Four minute mile

This morning I managed 8 minute miles so Roger Bannister was twice as fast as me. There are 15 lots of 4 minutes in an hour so he must have been running at 15 mph. I looked up the history of the mile as a unit of measurement https://en.wikipedia.org/wiki/Mile I knew it started with the Romans but I hadn't realised it was linked to furlongs, a distance I only know from horse racing but which apparently was how far oxen could pull a plough before needing a rest.

Motorways as electron energy levels

I have been thinking for some time about the idea that motorway lanes could be used as an analogy for electron energy levels. Slower, lower energy cars in the inside lane and faster higher energy cars in the outside lane. The inside lane should fill up first etc. Then there was the traffic jam. What would that represent? It helped me to realise that the exclusion principle must apply because you cannot put two cars in the same space at the same time which suggests that the cars might be fermions.

Ohm

I spotted this van on the motorway. It prompted me to look up Georg Ohm https://en.wikipedia.org/wiki/Ohm%27s_law The history of how he came up with his law is interesting; that he was able to include the internal resistance of the power supply without knowing and that he used thermocouples as his power supply. I need to try that.

New micro-hydro scheme at Boot

We found this on the Burnmoor Tarn track above Boot in Eskdale. I have not seen one being built before. I assume that they are excavating to install a pipe down to a turbine hall at the bottom. I was wondering why the water needs diverting down such a long pipe. The water mill at the bottom will have a short mill race but the water in the stream will have gained energy by its natural fall. I found this https://en.wikipedia.org/wiki/Micro_hydro which explains an equation power P=QH/k. Looking at https://www.gov.uk/government/publications/national-trust-renewable-energy-limited-application-made-to-abstract-water-and-impound-water-npswr023281/national-trust-renewable-energy-limited-application-made-to-abstract-water-and-impound-water says that they will abstract 792 cubic metres per hour or 13.2 cubic metres per minute. This is 2904 gallons per minute. For a 100kW scheme, that gives a head H of 183 feet. Burnmoor Tarn is at 250 metres and is about 200 metres above Boot. 183 feet is only 60 metres of vertical drop so that works.