What are the units?

 

This water trailer at Farmoor Reservoir would attract comment from Physics teachers. What are the units? If it is weight, it should be Newtons. But I suspect it must be the common usage, meaning mass so is probably kilograms but some calculations might be needed to discount pounds or stones.

Brilliant film of sundogs and double halo

 I have posted pictures several times of sundogs and halos around the Sun. The first lockdown was a particularly good time. The NASA APOD site has an amazing film from Sweden of a double halo https://apod.nasa.gov/apod/ap211228.html

Rudolph the Red-Shifted Reindeer

 Thanks to Ruth for this wonderful card.

Rudoph's red nose is emitting waves that spread out like ripples on a still pond when you chuck a stone in. However, notice that the ripples are closer together at A than they are at B. On a pond, they would be spread the same in every direction. The explanation here is that Rudolph is moving from right to left whilst continuing to emit ripples of light. Hence the ripples bunch up in front of him (shorter wavelength) but stretch out behind (longer wavelength). This stretching of the wavelength behind is called red shift. Red has the longest wavelength and any increase in wavelength of light is a shift towards the red end of the spectrum.

Using the Covid model to work out the R number

 There's not been a lot of use for the Covid model I developed last year because numbers have been steady. R has basically been 1. Things have changed with Omicron. They say numbers are doubling every two days. Applied to my original model, that gives R=3.2.

The number 6.4 in my model is the number of days it takes between one person contracting it and passing it on to the point where the next person can pass it on too. The figure is based on data I found in New Scientist this time last year so it may not apply to Omicron. They say R is between 3 and 5 at the moment. Here's what R=5 means. That's doubling every 14 hours if the 6.4 days still applies.

Colour changing LEDs for Wigton Christmas lights

 

The lights on the fountain this year are able to change colour. The spectrum shown above is able to move and change. I was wondering how single lights could do that. It turns out that each light is made of red, green and blue LEDs which are then turned on and off to make mixtures. See https://kitronik.co.uk/blogs/resources/how-colour-changing-leds-work

Christmas decoration convection and the new energy

 

We made rotating foil spirals and tried to figure out how to describe what was going on using the "new" energy descriptions for English schools. This vocabulary is based on the First Law of Thermodynamics so involves talking about heat or work crossing a system boundary. They have also made the vocabulary easier to digest by splitting heat into "heating by particles" and "heating by radiation. Work is similarly split into "mechanical working" and "electrical working". So energy flows from the candle into the air by the "heating by particles" pathway. The internal energy of the air increases. The extra k.e. makes means that the particles move further apart. This expansion and subsequent rise of the less dense gas will be via the "mechanical working" pathway. There are a lot of arguments about this and major holes to be picked in what I've just described. It was easier just to call it convection but I'm optimistic that the approach will give students a better handle on thermodynamics.

Field patterns at Silloth Docks

 I realised that the fence at Silloth Docks looks like vectors for electric field pattern. This is almost a radial field for a positive charge (almost because they don't quite trace back to a true centre)

However these are definitely showing a uniform field between two parallel plates. The bottom plate would be positive and the top plate would be negative because the convention is that electric fields point from positive to negative.

Extra pressure in the fermenting wine

 

The latest home brew is coming along. The gas produced by the yeast bubbles out quickly. It occurred to me that the pressure on the inside must be greater than the pressure on the outside by an amount measurable by the U-tube airlock. When a bubble is released, it does so through a column of water 8cm high. Pressure in a fluid = height x density x g. Density of water = 1000 kg/cubic metre. So extra pressure = 0.08 x 1000 x 10 = 80 N/m^2

Another nuclear fusion company

 In the summer I blogged about one company near Oxford working on nuclear fusion. Today the BBC is running a piece about another company the same area. https://www.bbc.co.uk/news/av/science-environment-59601560

Turbulent flow on the Wiza

 

Here's the Wiza last month on the factory corner on Station Road. The water is about to take a 90 degree turn to the right of picture. There was a prominent line of foam coming down which was gently rotating as shown. A will be slow moving water and B faster. This produces shear forces and then reflection from the bank at the turn must be adding to the rotation. I'm guessing that the rotation mixes air in to produce the foam.

Measuring the internal diameter of a U-tube

 Use the extending horns on the top of the Vernier callipers.

It needs to be done twice for each tube - with a 90 degree rotation of the orientation between the readings. This is to check that the tube truly is circular in cross-section.

James Gibson's Winter Wainwright Round

 To conclude this section on Cumbrian nodes and lines, here's congratulations to James Gibson on the fantastic achievement of a Winter Wainwright Round. The choice of the most efficient route between the nodes, the summits in this case, is a big bit of analysis. Steve Birkinshaw's route seems to be regarded as the gold standard. So what would its fractal dimension be?

I was able to cheer on yesterday but Mrs B made it to cheer at the finish in Keswick today.

Florence Mine Arts: more lines and fractal dimensions

 Having posted about fractal dimensions yesterday, we went to Florence Arts Centre in Egremont and found this:

These lines join disused railway stations in Cumbria but given a set of points, they could be drawn differently. It reminded me of the slime mould programme we saw last year where the slime mould was able to come up with the best connections between the stations, 

This leaflet muses about lines and also mentions the idea of fractals.

Yarn bombing in Wigton and fractal dimension

 

This wonderful piece of yarn bombing has appeared on top of the post box opposite Spar at the top of Station Road. It got me thinking about fractal geometry. The simplest example to look at is the Koch Snowflake. It is a line so it should have a dimension of 1. However by adding wiggles to the line, we are extending it a bit into space. They say not enough to be considered a plane which is a 2-Dimensional object, so the Koch Snowflake must have a dimension somewhere between a line and a plane, somewhere between 1D and 2D. In other words, it has a fractional dimension - this is where we get the term "fractal" from. The yarn bombing extends a 2D surface upwards into 3D space. Presumably its fractal dimension might be somewhere between 2 and 3.

Foliated rocks on Criffel

 

I read here that the rock on Criffel is not granite but granodiorite. More on that later. But it also said that the rock is foliated and I wondered what that meant. It's easily applied to metamorphic rocks because they form into layers but the crystals in igneous rocks can also be lined up as shown here. So do the mica crystals above show similar lines. Sort of, but it's not screaming out at me. This suggests mechanisms such as convection in a magma chamber or frictional drag from the walls of the chamber.

Expansion joint on the Wigton bypass footbridge

 

The sun was catching the expansion joint on the station footbridge this morning. I tried to look up the coefficient of thermal expansion of a concrete structure and found this. It is measured in microstrain per degree Celsius. It seems weird but I suppose that should be obvious because the actual expansion depends on the length - the longer it is, the more it expands. Strain = extension/original length. Let's simplify by saying original length = 10 metres. Then as far as I know, lowest temperature round here has been about -10 oC and highest 30oC. Coefficient of linear expansion = 12 x 10^-6 so strain will be that x 40 for the temperature range. So strain = 4.8 x 10^-4. Extension would be that x original length so about 5mm. Half a centimetre - enough to put big cracks into the structure hence the expansion joint. 

Xenoliths on Criffel

 

Criffel is a mountain made of a granite intrusion - the granite is white with flecks of mica, not pink like Shap. But its best trick is the presence of xenoliths where bits of the country rock around the intrusion have fallen into the magma and been baked in as it cooled and solidified. I've found small examples on the beach at Silloth before but there were huge examples in rocks in and around the lovely new path up from Ardwall.

A "hot" metal cover in the snow

 

It snowed yesterday morning. All morning, the snow refused to settle on this access cover for the drains. Metal feels cold to the touch so this seems weird. However, metal feels cold because it conducts heat well. The air trapped in the drain space will have been warmer than the air above so conduction will have been from below. This will have been enough to melt falling snowflakes. The ground around is loose and traps air. The trapped air acts as an insulator so cannot conduct from potentially warmer ground below. It's interesting that people talk about "stone cold" which suggests that rocks could also be good conductors.

Clocks in and out of phase

 

There are two clocks in our room that both have loud 1 second ticks. Last week they were out of phase by about 0.5 seconds so you could hear them both distinctly as individual devices. This week they are ticking in unison. The mechanisms will not be perfectly calibrated to 1 second so they should slide in and out of phase. 

Checking a gamma source with a mirror

 

It is good practice to check radioactive sources for damage before use. The safe way to do it, as recommended by CLEAPSS is to use a mirror. This is a gamma source and the gamma rays are not reflected back in the way that light is even though they are both electromagnetic waves. It ensures that the source is always pointing away from you. Always hold in 30cm tongs at arm's length.

Calcium silcate? A view from the Slag Bank

 Last week I was dealing with a question on metamorphism about the reaction between calcium carbonate (limestone) and sand (silicon dioxide) to produce calcium silicate CaSiO3. This must be wollastonite. But I finally got to climb to climb the slag bank at Barrow yesterday and I am wondering if this is largely artificial calcium silicate.

The layers in it look like lava flows or some of the banded volcaniclastic sediments in the Lakes. The pieces I picked up with very light and full of holes like pumice. Essentially, in steel making there is sand in the ore still. It is not pure haematite. To get rid of the sand, it is reacted with limestone. Both iron ore and limestone were readily available around Barrow. So calcium carbonate and silicon dioxide could indeed get to react. There is more information here and here.

The views were so good that I could see Snowdonia, the Isle of Man and Scotland. In the picture above looking up the Duddon, the Scafells are in the distance.

Sound insulation at Wasdale Head

 These barriers were in operation around a generator at Wasdale Head. 

I was very interested in the set of symbols that went with it. I'm not sure whether it adds kN to the load or is resistant to forces in the kN range. Also, does it reduce by 43dB or is what comes through less than 43dB?

So I tried their website. I really liked the frequency graphs lower down. This seems to show 43dB REDUCTION but at high frequencies only. This is important because I know from experience that it is the frequencies around 4000Hz that are most sensitive to the ear.

The Green Flash

 I had forgotten about NASA's Astronomy Picture of the Day site. Going back to it I found this wonderful film of the Green Flash. I have seen the Green Flash twice from the school trip to Normandy. I got very excited. It lasts a fraction of a second. 

Petrol price and American gallons

 

The price of diesel has topped £1.50 a litre for the first time in Wigton. We've paid that once in a remote place in the very far north of Scotland. We wanted to know what it would have been in gallons, knowing the fuss that was made when petrol first went over £1 a gallon. I work on the idea that there are 8 pints in a gallon and that a litre is roughly 2 pints so 4 litres to a gallon. It's actually 4.546 litres to a gallon, meaning diesel is £6.91. The problem is that I've discovered that an American gallon is different.https://en.wikipedia.org/wiki/Gallon It looks as though we were running different sizes of gallon in the UK for measuring different things until the mid-1800s when it was standardised. We seem to have gone with the liquid gallon but the Americans went with the corn gallon. Anyway, there are 3.78 litres in an American gallon. Our American friends reckon to have reached about $3.50 max meaning 92.6 pence per litre.

The Boyle's Law apparatus has leaked

 I had a surprise with the Boyle's Law apparatus because the readings didn't match those I took a decade ago. Here it is on 180kPa and the air volume is 33cm^3. A decade ago, the volume was 22cm^3. The ideal gas equation is pV=nRT. pV is 180 x 33 = 5940. A decade ago pV = 3960. So nRT must be bigger. The room temperature won't have changed much and R is a constant. Hence the number of moles of gas must have increased. Air must have leaked into the apparatus.

But it still gives results that show that pV=constant (roughly). Below we get 160 x 38 = 6080.

And finally 100 x 58 = 5800. So pV is always around 5900. This is one way of illustrating Boyle's Law.

Colorimeter photos and resolution

 

We used the absorbance scale, which is the bottom scale with the black numbers. The smallest scale divisions are every 0.05, which means that the resolution is therefore 0.05.

Here are the filters we used to find lambda max.

Here is the all important zero button.

Meniscus

 Liquid has surface tension. The particles would normally bond in all directions but at the surface they can only bond sideways and downwards. This means more bonds than usual are formed sideways creating tension. Where the liquid touches the side of a container, these bonds hold on. Gravity makes the liquid sag downwards in the middle. The sag is called the MENISCUS.

We always measure to the bottom of the meniscus.

Here are the two pieces of measuring equipment we used in class so that you can see the resolutions.

Rain before seven, fine before eleven

 Here is the scene first thing this morning.

By quarter to 11, the first sign of fine weather was beginning to appear in the west over the Solway.

My parents taught me the weather saying "rain before seven, fine before eleven" when I was a child; we were trying to be optimistic on wet holidays on the west coast of Scotland. When I became a teacher, an early lesson was that very few students had been taught it by their parents! It is based on the four to five hour transit time of an Atlantic front across the UK. It often doesn't work in mountainous areas like this one because the mountains can catch the cloud, especially if the weather is coming up from the Azores as it was the other week. But today it looks as though it's going to be all right.

Angles morts: blind spots

 

In France, the warning to cyclists and motorists about where they cannot be seen seems to have been called the "angles of death". In English, we call them "blind spots". The French is better. It is the physics that fixes this. Light travels in straight lines and cannot pass through metal. I'm interested that it includes a space right in front of the vehicle where the driver would not be able to see down.

Thirlmere Aqueduct at Greenhead Gill, Grasmere

 

The water from Thirlmere goes to Manchester through a tunnel that needs no pump - the water flows due to gravity alone. However, there are points where the gradient of the tunnel takes it above ground level. One such point is Greenhead Gill at Grasmere so they had to build two bridges to take the aqueduct out of tunnels and above ground. This included a change in direction. There is a brilliant film about the project that includes a visit to the site to be found on the Institution of Civil Engineers website https://www.ice.org.uk/what-is-civil-engineering/what-do-civil-engineers-do/thirlmere-aqueduct-and-reservoir

Gassy lava near Dockey Tarn?

 On the way up towards Nab Scar from Alcock Tarn, I found this boulder inn the path. There are rows of little indentations.

I was wondering if it was artificial but it continued into rocks nearby. This means that it is probably due to gas bubbles in lava. But why would the bubbles be so uniform in rows? It doesn't look as though there were repetitive layers forming on layers and that in each the bubbles rose to the top. So a mystery.

We went on to visit lonely Docket Tarn which sits on one of those wide ledges that is characteristic of the lava flows in the Borrowdale Volcanics around St John's in the Vale.