Origin of graphite at Seathwaite

We came down across the valley from the Seathwaite graphite mines. The workings form a vertical line up the other side of the valley. That suggests that there was a vein. But the rocks hereabouts are volcanic in origin. How did carbon get here? Turns out that it is a question that has been bothering people for years. Reading the info, it seems that the theory is that a later granitic intrusion through volcanic rock provided the heat to make organic compounds in earlier Skiddaw slates mobile. They must have coalesced in cracks in the existing rocks. The articles are very technical https://core.ac.uk/download/files/79/57913.pdf and http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=4489624

Boiling point of water on Great End

I was boiling the kettle for tea on Great End. I am aware that you need water at 100 degrees Celsius for decent tea. I'm also aware that water boils at a lower temperature with altitude, but I had never thought it might be noticeable in Cumbria. Great End is 910 metres. This website suggests that the boiling point is already down to 97 degrees Celsius http://www.engineeringtoolbox.com/boiling-points-water-altitude-d_1344.html I'd never thought about it but parts of America are high enough for this to be a problem domestically. Since it seems measurable, there's a project for the autumn with a thermometer on the Cumbrian mountains.

Blue Sun at Charnock Richard Services

 In the car park of Charnock Richard services on the M6, I noticed that the Sun was reflected in a puddle (see above). What was notable is that through my polarising sun glasses, the Sun was BLUE. I have noticed similar effects before but this was very clear. Reflection polarises light provided that the angle of incidence is bigger than the Brewster angle. Next time, I need to vary my observation angle in case different colours have different Brewster angles. Or is it that blue light is polarised one way and the other colours have different polarisation? I didn't think to rotate the polariser.

 And a wider angle to show clearly that the thin-film oil effect was only in the puddle on the right and was not responsible for the blue sun.

Time-base setting for a.c.

Here is the trace for mains alternating current. One time period is worth 4 squares horizontally, since the oscilloscope plots a graph of voltage on the y-axis against time on the x-axis. The frequency of mains a.c. is 50 Hz. T=1/f so time period = 0.02 seconds or 20 ms. So one square is worth 5 ms. Inspection of the photograph reveals that the time-base setting is indeed 5 ms per division. The oscilloscope must have had the calibration knob in the correct place as well.

Stress lines in the train window

This is what the train window looked like through the polarising filter of my sun shades. It looks like the stress patterns produced by polarising filters. But I have remembered that these are normally produced by putting the plastic between two polarising filters. Could it be that the polarised sky acted asns the first filter? I didn't think of that at the time so I didn't check the direction. The rainbow colours are also interesting. Why do they repeat? They look lke the thin-film interference patterns. I didn't think to rotate the filter to see what affect the polarisation direction would have.

Solar farm at Cambridge, Gloucestershire

I was peering through the hedge at this solar farm in Gloucestershire. Data shows that it receives 1000kWh per square metre per year. Say one panel is 2 metres wide and 10 metres long. Say 20 rows of 10 panels. That is 4 million kWh per year. If a typical medium consumption home uses 3300 kWh per year (https://www.ofgem.gov.uk/ofgem-publications/64026/domestic-energy-consump-fig-fs-pdf) then this field could power 1000 homes. I need to get more accurate figures for size and number of panels,

Polarised sky at Wigton station

I was stuck for 90 minutes on Wigton station looking for some Physics. I went back to the polarised sky idea. The Sun was to my left shoulder and diagonally up at about 45 degrees from me. I think my shades allow vertically polarised light through, so the polarisation direction is perpendicular to that 45 degree line from me to the Sun. So I will need to check that the angle changes at different times of day and at different times of year, depending on the height of the Sun.

Spin the engine on the La'al Ratty at Ravenglass

We were on the La'al Ratty. At the end of each journey they turn the engine by hand. How do the numbers look? For rotational motion, we don't use F=ma. We use torque = moment of inertia x angular acceleration. I inquired about the mass of the engine and was told 7 tonnes. I found out that it is 24 feet long which is 7.3 metres. I put these into the moment of inertia calculator at http://hyperphysics.phy-astr.gsu.edu/hbase/mi2.html#irod2 and it gave me 31085.8 kg metres squared. I pressed some scales against the wall at home and found my force was about 200N. The torque would therefore be 200N x 3.65m = 730Nm. This means that the angular acceleration would be 0.023 rad per second per second. This is about 1.5 degrees of turning per second per second. Then we need the angular equivalent of the suvat equations. This will need explaining elsewhere but by my calculation it would take 16 seconds to turn the train through 180 degrees. Not bad.

Amphours at the Transform Weekend

Paul was popular at the Transform Weekend near Ollerton when he turned up with this drill battery. Turns out that these days they also have USB ports so they can be used to charge phones and tablets. It's a big one - 5.2Ah. Amphours is a measure of charge stored, Current is defined as the rate of flow of charge. So I=dQ/dt. Hence charge transferred dQ= Idt. I is measured in Amps. dt can be measured in many different units. Here they have chosen hours. I normally use seconds because the unit "Ampseconds" is the same as Coulombs. Since 1 hour = 3600 seconds, 5.2 Ah = 18700 Coulombs. Anything that can deliver 5.2 Amps for 1 hour is amazing!

Satellite communication at RAF Defford

 I found this board in the museum at Croome in the Severn Valley. I went outside and spotted one of the remaining dishes.

Communication with satellites is line of sight. I teach that they use microwaves because the wavelength will pass right through the Earth's atmosphere. The wavelengths of electromagnetic radiation that will do this are limited. But the dish in the picture is so much bigger than a domestic television dish. Why might that be? In astronomy, I teach about what they call the GATHERING POWER or COLLECTING POWER of a telescope. The bigger the area the more Watts of power are collected. In terms of an optical telescope, it means that the image is brighter. That may be what is going on here.

Alum mine at Ravenscar

I have used alum when teaching about water purification. It is actually aluminium sulphate. Large soil particles in soil sink to the bottom of water under gravity but fine clay minerals don't. The stuff I've read says that the clay minerals are negatively charged. This means that they repel each other which stops them settling. They say that the alum when dissolved in water releases positive charges which attract the negative clay minerals forming particles heavy enough to sink and clear the water. This is called flocculation. This article explains it best https://en.wikipedia.org/wiki/Coagulation_(water_treatment) though I'm still trying to be clear about the difference between coagulation and flocculation. My description above sounds quite like a mix of the two...

Boulder clay at Robin Hoods Bay

 I was intrigued by the variety of igneous pebbles on the beach at Robin Hoods Bay in Yorkshire, which is in a resolutely sedimentary area. I also found this lovely piece of quartzite. I know that the nearest quartzite must be in the north of Scotland. Then I looked at the cliff behind me...

It is boulder clay deposited by a glacier. The stones in it are all quite angular, showing that they have not been subject to bashing during transportation by water. I have read that they can use the rocks in the boulder clay to plot the courses of ancient glaciers. Looks like there could have been a flow from Scotland.

What goes up...

In her book Warped Passages Lisa Randall uses a ball being thrown up in a brilliant explanation of red shift. As the ball rises, it loses kinetic energy but gains gravitational potential. It slows down. But a photon of light escaping from a gravitational field cannot lose kinetic energy because it has to move at the constant speed of light. So to have some energy to transform into potential it uses the E=hf equation for the quantum energy of a photon. If its frequency reduces - ie if it is shifted to the red end of the spectrum - it has transferred some of that energy.

Radio antenna at Flamborough Lighthouse

By the fog horn at Flamborough lighthouse there is what I think is a dipole antenna - ie a T-shaped wire - suspended between the two masts that you can see in the picture. I estimate that the masts are 20 metres apart. The top of the T for a dipole antenna is half a wavelength. So the wavelength would be 40 metres. Frequency = speed of electromagnetic waves/wavelength = 15 MHz. This seems to come in the High Frequency (HF) band as opposed to VHF. This sounds correct because https://en.wikipedia.org/wiki/High_frequency gives HF as used for maritime sea-to-shore communication and http://info.yachtcom.co.uk/HF-frequencies/ lists similar frequencies.

Induction cooker

We found this on the bottom of a pan in a holiday home. Induction cookers are interesting. Alternating current in copper wires under a glass cooker top induce eddy currents in the bottom of the pan. This heats the pan. Articles suggest the need for ferro-magnetic pans but in the lab I often take pains to show induction in aluminium. Perhaps it is to increase the flux. It is said heat quickly. They were popular in student accommodation because the hob doesn't get hot so can't cause fires.

3 quarts for Muster Mark??

 I found this quart pot in a pub in Broadway in the Cotswolds. A quart is 2 pints or one quarter of a gallon. Murray Gell-Mann had an idea that James Joyce's "Three quarks for Muster Mark" quote might have been him ordering 3 quarts of beer. Or at least that was his excuse for continuing to pronounce his particles "qwork". See the link http://www.finwake.com/1024chapter24/1024finn24.htm

Partial reflection

It was the annual Ogden Awards night at Lancaster University last night and we got our first view of the new department buildings. The lighting conditions gave us the perfect example of a type of partial reflection. You can see the inside of the building. It must be being lit by light from the outside which is going through the glass, hitting the room and reflecting back to us. Then light from the outside also reflects back off the outside of the glass showing us the world behind us.

Not Brian Cox on Not the Matterhorn

To celebrate the new BBC series with Brian Cox the author of this blog struck a pose like that adopted by Brian in previous series, atop a mountain whilst the drone camera circles him. I chose the rock on the top of Grey Friar that resembles the Matterhorn. You can catch the real Brian here for the next few weeks http://www.bbc.co.uk/iplayer/episode/b07k7m4z/forces-of-nature-with-brian-cox-1-the-universe-in-a-snowflake

Warped Passages by Lisa Randall

I've just finished this wonderful book. It explains how the Universe probably exists in more than the 4 dimensions that we can easily sense. Some theories work best in an 11-dimensional universe. Lisa Randall's own theory is roughly of a 4-dimensional brane that is somehow surrounded by a fifth dimension in which gravity can operate. She develops the history if the ideas from Newton onwards. The use of stories and allegories helps. Or you could catch some of the Youtube programmes she has done: https://www.youtube.com/watch?v=TuL7gSMzLlU or https://www.youtube.com/watch?v=SojWeJtYSr0&spfreload=5

Gauge invariance at Loch Muick

The bizarre tracks heading into the loch must have been for launching boats. They are right next to the boat house. The width of railway lines has always been referred to as the GAUGE. I had always wondered why this word had come into particle physics. The idea seems to be that on railways, the change of scale doesn't affect the product - you get the same thing, a train down a track. In field theory, it seems to be that if you change certain things, you retain the same basics. There is a symmetry across different "gauges". Presumably a different gauge of track would still put a boat in the loch. I'm just developing my understanding of this area.

Mental arithmetic in the hills part 2: km/h on Broad Cairn

We climbed Broad Cairn on Deeside and used the Queen's Land Rover track. I've been trying to learn km. I was successful in transferring from feet to metres a decade ago. But I still think of distances in miles. I know that we tend to average 1 mph over high mountains. But we had the chance to come back down vehicular access to a high hunting lodge. 4 km of track. Could we do it in 1 hour? So that is is 1 km in 15 minutes. 60 metres per minute would be 600m + 300m = 900m in 15 minutes. So roughly 1 metre per second. That's one big stride every second. Well, we did it. So I now have more of an idea about distances and speeds.

Flame probe for uniform field

I used this equipment to measure the potential in the uniform field between two parallel plates. I had a potential difference of 600V. I measured the angles of the gold leaf at 0 mm from the negative plate and then when it was touching the positive plate. I was then able to calibrate a scale to turn other angle measurements into voltages. I made this diagram to explain how it works, to amplify the explanation I gave in my previous post:

The closer the probe tip is to the positive plate, the more electrons are attracted from the gold leaf and the bigger the angle. Work is done against an attractive force to pull the electrons up so the angle represents potential energy. The graph looked like A below:

If we pulled the plates apart, the potential difference would be the same but the field would be weaker. So field strength is represented by the gradient of this graph. However, we went from - to + whereas the direction of an electric field is from + to -. To sort this out, we insert a - sign:

Field strength = - potential gradient