The end of the Moon

Never mind Comet Ison, the Moon has almost gone! Well, for this month at least. The Moon has nearly finished its monthly journey around the Earth. This picture was taken at 8am looking almost due South. In other words, it is highest in the sky at perhaps 9am. If it takes 27 days to go round the Earth, this high point in the South must be about an hour later every day. That means in 3 days time the Moon will be due South at around midday. It will be on the same side of the Earth as the Sun. The Sun will be lighting up the side that we can't see and the side facing us will be in shadow. In other words, in a couple of days we won't be able to see the Moon at all. Then after that there will be a faint sliver of a crescent on the right hand side this time - a New Moon. If the sky is clear I'll try to photograph it!

Cows need water

We were out on Hadrian's Wall the other month and found this water trough for cows. Our house doesn't have a water tank like this in the loft because the advent of the combi-boiler has removed the need for a hot water tank. But the ballcock is a fabulous invention. The plastic ball is less dense than water so it floats. The upthrust force on it pushes it up against the valve in the pipe, closing the valve. As the water level drops, the floating ball drops with it. Eventually there is so little upwards force on the valve that water pushed through to fill the tank. The floating ball rises to close the valve and cut off the water. An example of feedback!

 

An piece of art about waves

 

We went to Tullie House on Monday to see the Roman helmet but we also found a brilliant work of art. They would let me photograph it so you'll have to make do with a photograph of the leaflet. Alternatively you can go to http://www.artfund.org/what-we-do/art-weve-helped-buy/artwork/11956/ocean

It is about 1000 small ceramic pots laid out to be like a wave on the ocean. Waves are a transient thing. They are hard to pin down. Do you draw a graph of them frozen in one moment in time or draw a graph of how a single point on the wave moves with time? I suppose Natasha Daintry has chosen the former. I like its simplicity. I should have measured the wavelength. The amplitude decreases. What would we give for the wave speed? The exhibition is in Carlisle until March - plenty of time to go to see it.

DNA security at the substation

 

Substations are very dangerous but we were intrigued by the DNA sign. The yellow sign is obvious. Will need to find out about the DNA security system.

Kelvin Wake on Walla Crag

I always like climbing up above Derwent Water because you can look down on the wave patterns. Yesterday we were looking down from Walla Crag when the passenger boat came past. If you enlarge the photograph you can see the characteristic wave pattern behind the boat. It is called a Kelvin Wake after Lord Kelvin the Scottish physicist who first did the analysis. I haven't had time to read the mathematics in detail - I'll need to get back to you - but it seems that the angle may be just over 19 degrees whatever speed in deep water. I need to check this claim. I got my information from http://www.wikiwaves.org/Ship_Kelvin_Wake

 

 

When we were on the summit another bloke pointed out the marking in the rocks shown below. He said he thought it was a benchmark, which was a topic on this blog in September. I have checked the benchmark listing website and it's not recorded, so the jury is out. It doesn't look natural but it is flat, not vertical. It has no top line.

 

Red like a Spindle Tree

We found a Spindle Tree at Watchtree Nature Reserve. We surprised to find one so far north. Note the lovely red flowers. I teach that things are red because they reflect red but absorb the other colours of the spectrum that fall on them. The combination of the colours makes up white light. Quantum theory leads to some uncomfortable thinking for me. What do I mean by absorb? I'd normally mean that the photon energy matches an electron energy level jump so an electron jumps up. But that's what happens with the red. Then the electron falls and re-emits a red photon as far as I understand it. I'd say that the other photons are ignored by the atom as their energies don't match electron level jumps. So where do they go? They don't go though the object or else it would seem somewhat translucent. This needs working on.

 

Measuring the flow in Wigton

They put a depth measurement scale into the Wiza by the factory in the summer.

 

 

This followed the disastrous flood one Saturday afternoon in May. Here's what Station Road looked like. And, yes, that is someone canoeing down the road.

 

 

The study of fluid flow has its place in Physics. I hope someone will be able to find a solution. Perhaps data from the new pole will help.

The issue is flow rate. This means how fast the volume of water is shifted so it will be measured in cubic metres per second. At this point in Wigton, the Wiza is constrained in a narrow but deep channel. Water cannot be compressed into a smaller volume. In a liquid, the atoms are basically touching each other. If the new shape of the channel doesn't have a big enough volume for the water pouring into it there will be flooding. One way round the problem is to get the water flowing faster, or to pour the water in slower at the start. The other problem is that the water has a tight corner to turn at the factory so momentum will tend to make it carry straight on and out onto the road by the fire station.