Windhover over Newlands Valley

Walking on High Spy, we found ourselves above a Kestrel. You can just about make it out - digital zoom is not very good. It flies at just the right speed and with wings angled correctly to ensure that it stays still in the same place. Resultant force = zero. An exampled of Newton's First Law.

Solar power: return to Glenridding Hydro

We went past the intake for Glenridding Hydro. It doesn't look to have been damaged by the recent deluge. There is a small solar panel, presumably to power the controls. It looks like it can be contacted remotely, judging by the aerial. Vertically polarised, I note. The panel is roughly 0.4mby 0.2m. That's 0.08m. Using an online calculator, I got a figure of 0.61 kWh/square metre/day for these latitudes. That's an average power of 0.61 x 1000 x  0.08/24 = 2 watts. But it won't work at night. Another way is to say that if peak solar intensity is 1400 watts per square metre when the sunlight hits the Earth square on, then at 54 degrees north on top of as tilt of 23 degrees, 1 square metre will be stretched to 1/cos77 = 4.4 square metres. That reduces the intensity to 320 watts per square metre. For this panel, that is 320 x 0.08 = 25 watts at midday. We'd need about 50 watthours for the whole day to make the figures marry. Two hours of peak sunshine. Maybe not quite but not too bad. 25 watts for 12V power means 2 amps.

Baked Alaska

I first heard about Baked Alaska in a Physics exam question. Now I've eaten it. It is a dessert that involves putting ice cream in the oven. Why doesn't it melt? the answer is that there is a layer of meringue (basically whipped egg white) around the ice cream. It is this that needs baking. But it acts as an insulator. Insulators allow thermal energy through slowly so that if the dessert is only in the oven for a short time, the thermal energy can't reach the ice cream in time to melt it.

ZX81: my first ever computer

It comes to something when my first ever computer is on display in a museum. I guess that means I'm old. I first saw one in the Arts et Metiers in Paris 10 years ago but this one is behind glass in Manchester. I learned to programme Basic on this machine. The memory was 1kB and you stored programmes on cassette tapes. I never really got that to work. I found this old website https://www.cise.ufl.edu/~mssz/CompOrg/CDAintro.html which has a graph showing that the growth in computer memory size in the 1980s and 1990s was exponential. It makes predictions about what will happen in the Year 2000! I also found out about Moore's Law which is another exponential prediction: that the number of transistors in integrated circuits doubles every two years. This is at the heart of what it means to be exponential. You add a fixed amount to one variable (two years to time) and multiply the other variable by a factor.

Electrolysis of an aqueous solution of sodium chloride

We put some Universal Indicator into salt water and put in graphite electrodes. This is what happened. The solution contains four types of ion: H+, Na+, OH- and Cl-. Opposites attract. The Cl- ions go to the anode on the left and give up an electron each. Two chlorine atoms then bond covalently to form molecules of chlorine gas. This is acidic, hence the red colour and a bleach, hence the white. There was a strong smell of swimming pool in the vicinity! Now those electrons given up by the chloride ions are pumped round the circuit and are given to the H+ ions, which had been attracted to the cathode. Bubbles of hydrogen gas form at the cathode. That leaves the Na+ and OH- ions in solution, Sodium hydroxide is a strong alkali, hence the purple. I have not made much progress in my pursuit of electronegativity as to why some ions stay in solution and some don't. Also, I'd like to know why chlorine bleaches.

The hand hypothesis

Sam's hand swelled up on Starling Dodd. We discussed the various factors and came up with different hypotheses. One was that a heavy rucksack was restricting circulation. So the next day he walked without a rucksack and his hands were not swollen, as shown. So is the hypothesis proven. It's not that easy. It wasn't a controlled experiment. We didn't walk for as long. we didn't climb as high. The weather was roughly the same. One event doesn't constitute a pattern. We'd need a lot of repeat readings and repeats in subtly different conditions. My simple Physics experiments involve situations that are simple to control. That's why they are the original laws - they were the first to be discovered. But more complex situations are much harder to control and prove.

Resultant force in Rake Beck

The picture above is of the waterfall on Rake Beck. I climbed above it to take the next photograph and got soaked.

The waterfall was going uphill!

Resultant force is the combination of opposing forces on an object. In this case, you have the weight pulling downwards on the water due to gravity and the wind pushing upwards. Normally, the weight is far stronger than the wind. Not only does the water go downwards, but as there is a resultant force, it accelerates downwards. I was unfortunate that the wind was so strong that it was stronger than gravity. The resultant force was upwards and the water accelerated at me.

Tea and coffee pots at Glenridding pop up cafe

We were walking from Glenridding and went to their pop up cafe in the village hall. The toilets were wrecked in the floods and they served us wonderful tea, coffee and cakes as part of their fund raising efforts. The tea and coffee pots were shiny silver. This is a well-known piece of Physics. Silver surfaces are very poor emitters of infra-red heat radiation. The lower the rate at which thermal energy is emitted, the longer the drink remains at a good temperature for drinking. But I wondered if the different shapes of the pots was to do with Physics. Internet answers such more culinary reasons. They say that tea pots have a wider cross-section due to the need to stir the tea to disperse the flavour. If the coffee has been made from ground coffee, the grindings will sink to the bottom. The taller the pot, the more liquid can be decanted before the grindings start to come out to. Of the various answers on the Internet that you can choose, I thought these the most sensible. Do your own research and see what you think!

A potential well on Great Borne

We found this shelter half way up Rake Beck on Great Borne. It looks like an old Cumbrian grouse butt. That's Ennerdale Water in the background. It reminded me of the potential well for alpha particles escaping from a nucleus.

The idea of a potential well is an analogy: energy is needed to remove a ball from a well by doing work against the attractive force of gravity and this can be a model of removing an alpha particle from the nucleus by doing work against the strong nuclear force. This potential well sticks out above ground level because moving alpha particles from outside towards the nucleus results in energy being stored because of work done against repulsion. This is like going uphill. The weird thing that can happen is that alpha particles inside the nucleus can tunnel out through the walls.This is called quantum tunneling. It would be like sitting inside the grouse butt and suddenly appearing sat outside without climbing out.

A trip to Watchtree: Why won't this snowman melt?

We went to Watchtree Nature Reserve. This snowman was still almost a metre high. It occurred to think about the Physics behind its failure to melt away. What is it about putting the snow into a shape like this that makes it take longer to melt? First observation is that you compact the snow and compacted snow always seems to take longer to melt. To compact it, you squeeze the air out. Could that help? The thermal energy that melts the snow must be coming from the air on a day like today when the Sun is not out. The air is warmer than the snow so there is a temperature gradient. Maybe lack of air spaces stops warmer air circulating. But air filled snow is supposed to be a good insulator. Also putting the snow together in a big block reduces the surface area and thermal energy can only get in through the surface. I think this is likely to be the biggest factor but I will think more about it. Frustrating not to be able to explain such a simple thing.

Los Guinchos power station on La Palma

The total population of the island of La Palma is apparently about 80000. That's 20000 less than Carlisle. How do you power an island that is a long way from anywhere? There is a small power station down by the harbour at Santa Cruz. Here it is photographed from our ship. I've had to work hard to find information. I realised that searching in English wasn't a bright idea but I don't speak Spanish yet, so online translator help later ... http://endrino.pntic.mec.es/jhem0027/centralescanarias.htm http://www.initec-energia.es/section3.cfm?id=3&side=134&t_id=134&rid=69&lang=en http://www.initec-energia.es/section3.cfm?id=3&side=134&t_id=134&rid=82&lang=en The suggestion is that there have been a lot of small oil powererd generators patched together and that the total output might be around 50MW. Given that Bothel wind farm near here is supposed to be 10MW... The power grid must work at a much lower voltage because the insulators on the overhead lines were much smaller than I'm used to.

Shadows at Blenheim: low intensity winter Sun

On virtually the shortest day of the year, I was looking at shadows at midday in the grounds of Blenheim Palace with my niece. Look how long the winter shadows are, because the Sun doesn't get high in the sky. The tilt of the Earth means we lean away from the Sun, hence it looks lower in the sky. Your shadow is the sunlight you block. Now your size doesn't change between summer and winter: you must be blocking the same amount of the Sun's energy. But your shadow is bigger so the Sun must be throwing the same energy over a bigger area. We say that the intensity of the sunlight is lower in the winter. In summer, midday shadows are shorter. The same amount of solar energy is thrown at a smaller area. It will have a higher intensity. We are the same distance from the Sun summer and winter: it is the angle at which the sunlight hits the Earth that makes the difference. Here's a diagram to explain it:

Facing south on Bowness Common

 We walked across Bowness Common on the Solway and came across this. I took the photograph at 12 noon so my shadow should be lined up with due north. It's not perfectly aligned but not bad.

 My classes seem to have lost the idea that you can tell south because it is the direction you point if you face the Sun at midday in the northern hemisphere. People think that compasses define the directions but the Sun defined the geographical directions first before compasses were invented.

Silent Night - or - Do you want to build a snowman?

This was the view from Wigton this morning. Wigton is very quiet compared to the constant noise of traffic I was used to in the city but you can still hear the hum of the factory in the night if you tune in to it. Not last night - it was very, very quiet. The snow that fell was incredibly dry and powdery.It was very good at absorbing the sound energy. Sound is a longitudinal vibration. The sound would penetrate the snow instead of being reflected and this has a damping effect. The sound would make the loose snow flakes vibrate a little bit but the likelihood is that they would be bad at re-transmitting that vibration to the air. The energy would thus likely be dissipated as tiny molecular vibrations - in other words as microscopically small amounts of thermal energy. Not enough to melt the snow. To test the properties of the snow, we built a snowman. The extreme powdery nature of the snow made it hard for it to stand up...

Terminal Velocity on Castle Crag

We went up Castle Crag and had a lovely time in the snow. The flakes are falling but not accelerating. They are clearly going at a steady speed. What happens is that when they leave the cloud, only the force of gravity acts on them. So there is a resultant force, because at that point in time there is no counter force, only the driving force of gravity. So the flake speeds up. As it speeds up, the air resistance counter force increases. So the difference between driving force and counter force is less. It still accelerates but not by as much. But it did speed up a bit, so air resistance goes up again by a bit. Eventually, air resistance counter force is as big as the gravity driving force but they act in opposite directions so the resultant force is zero. Now there is no acceleration so the flakes carry on at a steady speed. This is called the TERMINAL VELOCITY. Later the flakes were much smaller, more like pellets. With a smaller surface area they experience less air resistance so they have to accelerate more to before the air resistance is as big as gravity. They have a higher terminal velocity and were visibly falling faster, And if you were wondering what the view was like before the snow started falling...

Testing a hypothesis by Derwent Water

If you've seen the new Star Wars film, you might recognise Derwent Water, which was in about 30 minutes of the film. We're expecting crowds later in the year, but there weren't many people around today. The new sign boards had a testable statement: that it would take 2 minutes to walk to the lake. If you can test that prediction, then we could call it an hypothesis. So I did time it. I'm not a slow walker but it took me nearly 3 minutes. Is the hypothesis correct? Well, we'd need to test it on many more people and on many more occasions. One piece of data is a start but more is needed. I could do repeat readings myself. They won't all be the same although they should be similar. These small variations would be called RANDOM ERROR. It is important to have control variables in any test to make it fair. So the same person would be a start because a person with longer legs might get there in less time because each stride takes them further. If we then found that it worked with different people, we could say that the test was REPRODUCIBLE because different people had done it and got the same pattern. These are some of the scientific investigation words we've been learning this week. And sadly no sign of Princess Leia today... :(

Wind power on Gran Canaria

I spent time on the Canary Islands wondering about how you supply electricity to such isolated communities. We have such centralised power stations and a big grid. I'd have thought it would have been through renewables, but apparently not. Our guide on Gran Canaria quoted a figure of 3% of their electricity coming from wind power. That's despite this article that I found http://www.theguardian.com/environment/2014/jan/06/wind-power-spain-electricity-2013 which says that a lot of Spanish electricity now comes from renewables. But I loved the comment underneath the article from someone claiming that the turbines pictured above spend most of their time at rest! The Canaries are served by Trade Winds from the north east and the scirocco from the Sahara. These turbines are on the east side of the island so should be well positioned.

Solar observatory on Mount Teide

 The Mount Teide volcano National Park on Tenerife has an observatory as well. This time it's a solar observatory for looking at our nearest star.

You might wonder why they'd put a telescope there. But look at the view from above it looking down. The clouds that are blown in by the Trade Winds are well below the level of the telescope so there will always be good views of the Sun. You can tell from the arid landscape that it doesn't rain much - although there were small patches of snow on the top of Mount Teide itself. Also, being about half way to the Equator from Wigton, the differences in daylight hours between winter and summer are much less severe.

Power station in Portugal

Taken from a moving coach, I think that this is the Ribatejo natural gas power station on the outskirts of Lisbon. It is one of the biggest in Portugal in terms of power output, having a capacity of 1176MW according to https://en.wikipedia.org/wiki/List_of_power_stations_in_Portugal It looks a lot smaller than the UK power stations I'm used to but I'm not sure it's capacity is that much lower. For example, Ferrybridge looks massive but has just under double the capacity. I was taken by the red and white chimneys and pylons. I can't find a reason but surely it is for aircraft. Why don't aircraft seem to be a problem in the UK? Also, they say that one third of the white storks in Portugal nest on pylons. But that can't be the reason because the chimneys are painted.

Force 9 in the Bay of Biscay

This is what Force 9 looks like. I took the photo so that I could write about the Beaufort Scale. I've found out that Beaufort was a naval officer nearly 200 years ago and the scale was an attempt to standardise the wind speed reports to help the sailing ships that were what the navy used in those days. He gave accurate descriptions of what should happen. These days it is linked to wind speed. In our case, it mean that the swell was about 10 metres high. It's an interesting example of an attempt to put numbers to something that was difficult to measure at the time.

Seeing: Telescopes on La Palma

One of the things that I really wanted to see in La Palma was the collection of telescopes. Turns out that they are perched high on the rim of the gigantic caldera. I finally spotted them through binoculars! They are high on the mountain because they get better "seeing". Stars twinkle because of the motion of layers of air in the atmosphere. Even on cold nights there is often a lot of convection round here as the land cools down. Air of different temperatures means different refractive indices so images get bent and then move as the layers move - there's the twinkling. The higher you are, the less air above so the less distortion. The volcanoes in the Canaries poke out above the main cloud layer. There is also little light pollution because so few people live on La Palma. The views are simply better.

The air gets colder as you get higher: Arnison Crag

We went into the hills for the first time this year, climbing small hills above Patterdale. No temperature inversion here: the air clearly gets colder as you get higher hence the precipitation is snow higher up. You can see a few flakes in the second photograph. So does the precipitation start as snow and then melt on the way down to lower levels? Is it just because it has to fall further and down into the warmer air? And why would the air be warmer closer to the ground on a miserable day like today with no sun?

The Christmas Pudding Model

Well, OK, it's technically called the Plum Pudding Model, but it's the same thing. John Dalton from Cockermouth, just down the road from here, revived the idea of atoms. When JJ Thomson discovered electrons in 1896, that caused a problem. Electrons were negative but atoms were neutral. That meant that there must be positive stuff in the atom. No positive particles had been discovered so the hypothesis was that the electrons were like negative currants in the positive dough of a Christmas pudding. The positive was smeared throughout. This meant a prediction that when positive alpha particles were fired at atoms, there would be no resistance because the positive in the atom was spread out so thinly. Turned out to be wrong ...

Constellations

Constellations are a wonderfully silly idea but I love them. The idea of seeing patterns in the stars - space is 3D and the stars we link together are just stars that are in the same direction as viewed from Earth. They may be vastly different distances along that common direction. But the seeing of patterns is a way that humans make sense of the world. And it helps us to find our way round the sky. These boards are in the cable car station for Mount Teide on Tenerife. The night sky is supposed to be very good up there!

Igneous intrusion on La Palma

I was able to catch up with much more recent volcanic features on the Canary Islands. Most striking was the fact that it has never been smoothed and widened by glaciation like the features in northern Britain. Today I've picked out a volcanic dyke in the Caldera de Taburiente on La Palma. I don't speak Spanish but the display board shows molten magma welling up through cracks in pre-existing rocks, It shows the temperature gradient from the middle of the feature and cooling as it moves out. The molten rock bakes the country rock, resulting in a zone of metamorphism. The bottom photograph is a detail of this. But look how much harder the dyke is than the surrounding rock, which has worn away leaving the dyke standing out like the ones I saw on Arran.

Xenolith at Skinburness

 We found this rock on the beach at Skinburness. It is Criffel granite. You can just see Criffel under the cloud across the water.

Criffel granite is an igneous intrusion. The hot magma welled up under the surface but never broke through. Granites can take up 1 million years to solidify so they grow big crystals. However, the grey lump is not a crystal. As the magma came up, it pushed into rock that was already there. They call this "country rock". Sometimes bits break off and fall into the magma. The rock solidifies around the intruder. The intruder is called a xenolith.