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.