Turbulence at Silloth

The tide was ebbing fast at Silloth tonight. There was a clear flow out to sea from right to left. Look at what happens when it crosses the submerged pipeline in the middle of the picture. It changes from laminar flow to turbulent flow. This means that the Reynold's number must have exceeded a critical value. Reynold's number is a ratio that depends on several key factors. Speed is one of them and size is another. One way of reading this is that the flow rate must be maintained but the pipeline decreases the cross-sectional area of flow so the speed increases. Another approach would be to say that the size changes. This is taken as the hydraulic diameter if it's flow inside a pipe - this isn't. But Reynold's number is proportional to size and saying the depth decreases might suggest that Reynold's number has decreased. It clearly hasn't. https://en.wikipedia.org/wiki/Reynolds_number

Supermoon eclipse over Wigton

 I hadn't heard of the term "supermoon" until last night. As with any astronomical object, the orbit of the Moon is not a perfect circle. It is more of an oval - an ellipse. That means that at some times in the month, the Moon is nearer the Earth than at others. When this coincides with the full moon, they call it a "supermoon". We were warned that at 14% bigger/brighter, we'd struggle to tell the difference. And in truth, I'd agree. There is that optical illusion thing where a full moon looks huge if it is near the horizon and you have earthly objects against which to compare it.

Here is the first part of the eclipse. The camera is set the same so you can see how much it has diminished. I was unable to get a picture at all during the fainter red light near totality. For those  who don't know - this is when the Moon edges into the shadow of the Earth so is able to reflect far less light than normal.

Robert Wilson of Dunbar - ship's propeller

I was thinking about the ship's propellers on the ferry to Arran and I remembered that I'd seen this in Dunbar harbour. I've been looking at the issue and have begun to wonder how you choose how many blades to have and what angle to set them at. It turns out that some planes and wind turbines can vary the angle (or pitch) of their blades. Wind turbines always seem to have 3 blades but the one in the harbour has 4. This will need looking into. I like the idea that the young Robert Wilson actually did experiments to find out what was going on.

Flow rate at Wilf's in Staveley

 I took these pictures from the balcony of the wonderful Wilf's cafe in Staveley. My ancestors come from round here and there are lots of people with my name here. Wilf's used to be a wood turning mill. My ancestors worked in bobbin mills like this. The weir is to hold up and redirect the water to power the mill. I noticed how much faster the water emerged from the duct. Then I remembered volume flow rate. Water flows by volume, and the volume per second = cross-sectional area x speed. This should be the same for the river above and the duct through (not quite true because there was water redirected to the mill). The pipe has a smaller cross-section so a higher speed. The depth seemed the same in bot. The river was about 10 metres wide and the pipe 50cm wide so the speed would be 20x faster.

I also noted that the wheel to close the hole was much bigger than the ratchet. Equal work done at each end means smaller force on the bigger wheel,

Surveying for the Haweswater Aqueduct

 A walk over Grey Crag and Tarn Crag from Sadgill in Longsleddale allowed me to inspect the survey stations for the Haweswater Aqueduct. You have to be able to see each station from the previous. the first one I found was on Great Howe. It's about 2 metres high. There is a lower one visible down the hill beyond the wall.

 The one on the top of Tarn Crag is about 4 metres high. My first one appears as a dot from it.

 And looking north it is just possible to pick out the one above Haweswater itself.

They must have been measuring angles and distances, The aqueduct is deep underneath and the water flows under gravity. I'd love to know how they turned these measurements above ground into tunneling data. There is interesting information here http://www.tathamhistory.org.uk/aqueduct.php

Bronze Age sunset at Brat's Moss stone circles in Eskdale

I've known about these stone circles above Eskdale for years but never visited. They turned out to be much better than expected and really worth a visit. They are high on a hill because in the Bronze Age because the valleys would have been thickly wooded in those days. The moor was the only sensible place to live. I was thinking of the idea of the stone circle as an astronomical observatory plotting the time of year. Maybe some of the first science ever done making the farming year understandable. If that's the case, then there should be a logic to how the stones are arranged. One oddity about each of the five circles on the moor is that each has a central marker. So I stood at the centre of the biggest circle and took a bearing to one of the most prominent stones in the outer ring, riughly south west.

 A bearing of 240 degrees. If it is astronomical, being on the west side it's most likely to be sunset. But how would you know when without going? It occured to me that it must be possible to calculate the bearing for sunset at any given latitude so I checked online and found www.suncalc.net. Here's what I found for Eskdale for roughly the shortest day of the year.

The sunset bearing is about 230 degrees measured with a protractor. Close but not touching... but the precision of both measurements is poor. The only way to test my theory would be to go for sunset on the shortest day!

Slow conduction of manganate ions

This experiment is an old favourite from the Nuffield course. The bulldog clips are connected to about 30V. The filter paper is soaked in ammonia solution and a crystal of potassium manganate (vii) is put onto the filter paper. The top clip was positive. The negative manganate ions are coloured (manganese is a transition metal so has coloured compounds). The coloured ions are clearly attracted to the positive. They travel slowly - 5mm in 1 minute. This is in contrast to the seemingly instant movement of electricity when you flick a switch. In reality the charge carriers move haphazardly, crashing into things. They seem to go slowly and we can calculate their "drift velocity". Electricity seems instantaneous because they all move together so there is always movement in any given part of the circuit.

Jonathan Otley of Keswick

See if you can find this when you are in Keswick. I looked him up http://www.geog.port.ac.uk/webmap/thelakes/html/otley/otley07.htm I'm impressed that he corresponded with John Dalton and Adam Sedgwick who were world class scientists. I like the idea that he cut a notch on Friars Crag to allow measurements of the level of Derwent Water to be measured,. He sounds like the sort of amateur scientist I'd like to be.

Dating at St Catherine's Church Eskdale

The walls of St Catherine's Church are slightly pink. That's because they are made of rocks of Eskdale granite which has a lot of feldspar in it. It's called the Eskdale pluton. Pluto was the god of the underworld and this describes the way the molten rock intrudes from below, never reaching the surface but eventually solidifying. I looked up information on the rock http://jncc.defra.gov.uk/pdf/gcrdb/GCRsiteaccount297.pdf and was interested to read about the method used to date it. The rock contains crystals of zircon, which is zirconium silicate. This can trap uranium atoms. There are two possible ways for isotopes of uranium to decay into isotopes of lead but there is no way for lead to be ordinarily part of a zircon crystal. Any lead in there must have come from decay of uranium. If you count the atoms of uranium and lead (this could be done with a mass spectrometer) then you can use an equation linking the ratio to the age of the rock. https://en.wikipedia.org/wiki/Uranium-lead_dating Since long decay chains are involved, I wondered whether some of the uranium would have decayed but not yet become lead. Most of the decays are very fast.  A couple of the intermediate isotopes have half-lives of the order of tens of thousands of years, which must be why the technique is said to be valid only for rocks older than 1 million years. And for the record, the rock is dated as 452 +- 4 million years.

Wavelength matters on Caudale Moor

A funny day for electromagnetic waves. Visible light, wavelength around 500nm, was unable to penetrate the fog, It is scattered by the tiny water droplets. But I had 5-bar mobile phone signal. These are heading towards the microwave region so must be up towards 1cm wavelength, far too big to be affected by fog droplets. It's all about the wavelength.

Machrie stone circles on Arran

 I have an idea that our Neolithic ancestors were the first scientists. If the board below is right (and the picture above shows the view up the Machrie Glen) then the stone circles record astronomical observations.

 I like the use of levers in the picture above. The stones below would be hard to handle otherwise,

Cyclopedean tors on Goat Fell

Goat Fell on Arran is granite. Granite is intrusive - magma that wells up but never reaches the surface. It can take a million years to solidify so it grows large crystals. As it cools, it shrinks. This tends to create horizontal and vertical cracks in the rock. The tors created are called Cyclopedean because they look like buildings for giants, made out of huge regular blocks. The Cyclops were giants of Greek mythology. I read up on the granite tors in one of my favourite books, Ronald Turnbull's Granite and Grit. He makes the obvious point that prominent tors on ridges as here and in the Cairngorms should have been wiped out by glaciation. He then explains that the tors actually form underground. Acidic water seeping down from vegetation dissolves the crystals in the cracks in the granite. This leaves blocks underground surrounded by gravel. Eventually, the freezing of the ground in the winter which pushes the gravel up as the water expands into ice causes the gravel to fall back downhill as the ice melts. This clears the gravel over thousands of years from the summit ridges leaving the tors prominent as we see them today.

Wake on Ullswater

Whilst walking above Ullswater, I spotted this unusual wake from a boat. It's not an even v-shape but has a scalloped edge, certainly on the right hand side as seen above. I wondered if perhaps the boat has accelerated and thus whether the speed of the boat has an effect on the width of the wake. That must surely be the case as I think that's what results in the sonic boom of aeroplanes. The wind was blowing from left to right across the upper end of the lake. The lake gets shallower as it approaches the right hand side. I doubt it's a refraction effect because my map doesn't show it getting shallow very suddenly.

Kildonan dyke swarm on Arran

On the beach at Kildonan at the south end of Arran there are a large number of these linear rock structures on the beach. They look like concrete sewage pipes at first glance but they are one of the most amazing bits of geology I've ever seen. About 60 million years ago basic magma - that's the type from which the oceanic crust forms - welled up through cracks in the sandstone rocks hereabouts. It solidified to form these dykes. They are tougher than the surrounding sandstone and so stand up like walls.

 Clearly such hot magma will affect the surrounding sandstone. See the picture above. There is something called contact metamorphism where the heat changes the existing sedimentary rocks. I suspect that's what has happened here. These sections are harder than the surrounding sandstone and have also resisted erosion.

 The dykes go on as far as the eye can see. I was amazed to discover that there are only 25 known dyke swarms on Earth. This is one of only 4 in Europe. Here, some of the dykes are basalt from the basic lava and some are dolerite. There was apparently some mixing with granite magma - the sort of molten rock from which continental crust is made.

The village seems to be based around the biggest dyke of all.

In and out of phase on the Arran ferry

I was watching the radar aerials on the top of the ferry at Ardrossan whilst we were waiting to go on. There were two horizontal rotating aerials. The top one was abput twice the length of the lower one. The lower one was spinning about twice as fast. This meant that sometimes they had their full length facing me. At this point we'd say that they were in phase - doing the same thing at the same time in their rotation. They'd spin a bit longer and whilst the top one was showing it full length, the bottom one would be end on. Now we'd say that they were 90 degrees out of phase. Next, one would show its full front length but the other would show its full back length. They were 180 degrees out of phase. And so on. Fans of maths will realise that 180 degrees out of phase is the same as pi radians out of phase.

What would it be like to have no genes?

This morning we made a large paper chain model of a chromosome by stringing genes together, I was asked "what would it be like to have no genes?". This is an excellent question that pushes at the difference between Biology and the physical sciences. I suppose the answer is that you'd be a rock, or a lump of metal or water. No genes means no life because no reproduction is possible.
Genes are the smallest unit of inheritance. This means that they are the smallest instructions that we get from our parents that tell our cells how to work. Chromosome are long strings made from different genes joined together. They are found in the nucleus of all cells except for red blood cells, which have no nucleus. They are passed on to the next generation by sex cells (gametes).

L6 Estimation question: how high do they fly above Wigton?

If you make this picture bigger, you will see a small white dot just to the left of my little finger. That's a plane high over Wigton heading for America. Imagine a triangle from one side of my little finger down to the camera lens and back up to the other side of my little finger. The camera was about 60 cm from my little finger. Show that the angle in the triangle is about 1 degree.
So my little finger represents an angle of about 1 degree when held at arm's length. Compare my little finger to the plane. If my little finger is worth 1 degree, what is the plane worth?
Find out how big an aeroplane and use the triangle idea to calculate how high the aeroplane is.

BBC 2 Horizon programme on the multiverse

There was a wonderful episode of Horizon last week on the state of multiverse research. This is the idea that there is more than one universe out there. I was familiar with the quantum idea that when a yes or no decision is made, the universe splits in two to allow both possibilities to exist at the same time. This is an alternative to saying that things remain in a state of quantum uncertainty when you are not looking at them: Scrodinger's Cat is the usual explanation. But the programme also goes into cosmological views on the multiverse. It seems somehow more convincing when there are competing models... Here's the link, valid for a while yet: http://www.bbc.co.uk/iplayer/episode/b0695t56/horizon-20142015-17-which-universe-are-we-in

Circus balancing act

Really impressive balancing act at Zippo's Circus. It must be the case that the line of action of her weight down from her centre of gravity must act through her base area or else there would be a resultant torque and she would topple. Hands give a bigger area so she balanced on top of a pole which would make it harder. She then raised herself by catching and adding bricks under each hand, one at a time.

Flying a kite in Silloth

 After the observations of big kite and little kite on Silecroft beach I resolved to make some measurements. Tonight I got a spring balance to measure the tension in the string. The 1N reading was probably a bit low, with the spring balance being upside down. I felt the tension in the string and then felt the newtonmeter - felt more like 2 Newtons in truth. I estimate the angle of the string as 45 degrees to the horizontal. The kite itself leans forwards - the string is not perpendicular to the kite at the top so I've assumed it was at an angle of 40 degrees above the horizontal. I measured the kite - 69cm by 59cm so area was 0.41 square metres. I assumed the density of air as 1 kg per cubic metre. I calculated the force of the air on the kite by assuming a component of the wind normal to the kite and that the air stops dead when it hits the kite. I then used Newton's Second Law as rate of change of momentum of the normal flow of air hitting the kite. My method is shown below.

I put in the numbers and got 3.6 metres per second as the wind speed. That's 13 km per hour or about 8 mph. That doesn't sound too bad. The wind speed was too low to fly the bigger kite. Will repeat with a stronger wind and try to measure the angles more accurately. Thanks to Adam for holding the kite!

Root Mean Square in Wigton

I spotted this sign today. The letters R.M.S. are important in Physics.Think about the molecules in the air. The distribution of velocities is random. That means that there will be as many going left at 6 m/s as there are going right. We could say left is 6 m/s and right is -6 m/s. So the average velocity of all air molecules would be ZERO. That's nonsense. So what we do is SQUARE all of the velocities. That removes the minus signs so we get a sensible non-zero MEAN. To get the number back to normal size we have to take the ROOT. Put backwards, that's ROOT MEAN SQUARE - RMS.

Update on the wave-like pattern: Aira Force

This is Aira Force, much beloved of William Wordsworth. Foam bubbles from the waterfall travel across the pond and gather in the corner as shown below...

The shape and structure are exactly as seen last week above Hayeswater, except that there is no gap between the semi-circular wavefronts. I will look out for more examples.

Structure: abstract at UEA

We went to see an exhibition of abstract art at the Sainsbury Centre at UEA in Norwich. The exhibition featured the work of John Golding, as shown on their leaflet. The commentary emphasised the way that he gives structure to an otherwise abstract space. That reminded me of several things in Physics. One is the way that physicists go on about structure in the Universe. It looks random to me but the way that galaxies are grouped into clusters throughout space is significant. A second is the Hertzsprung-Russell diagram for the lifecycle of stars.

I was told that the pattern was amazing. I wasn't impressed first time I saw this plot of the brightness of a star against star type. I'm used to straight line graphs/ And yet there is a clear structure here. Golding's paintings remind me of this.