Will I be able to react in time?

 

The drought down south means that the trees are shedding leaves sooner than expected. I was lying in the shade under this conker tree and hoping that the conker directly above my head wasn't about to drop. Would I be able to react in time? It was 3 metres above me. Using s=ut+1/2at^2 means that it would take 0.8 seconds to fall on me. If my reaction time is 0.2 seconds I might just be able to take evasive action.

Is this an electric motor at Saddlestone Quarry?

 

Bramley Engineering still seem to make lifting gear. This shed is above a big cable that goes down the hillside on Coniston Old Man. Looking at the hollowed out shell below, I think that the two angled metal bars with cupped tops might be stator cores for an electric motor. It is rusty so they are definitely ferrous. The idea of an electric motor is that electric current flows in a rotor and basically acts as an electromagnet that repels from a permanent magnetic field. In many motors, the "permanent" field is actually provided by proper electromagnets. These are coils wrapped around iron cores and are called stators because they don't move. These certainly look like stator coils.

This is the shed at Saddlestone Quarry in which the engine is housed.

The Winchester measure and enforcement of common weights and measures

 

I've been reading EP Thompson's book "Customs in Common". He spends a lot of time describing the way ordinary people tried to avoid being ripped off when buying grain and the way that there were sometimes price spikes that precipitated riots. I have posted before about the difference between the American gallon and the British gallon. The former was based on a volume of grain called the Winchester. EP Thompson describes how an Act of Charles 11 tried to set this as a standard across England for corn purchase but that there was resistance. He says that traders wanted to keep things uncertain and not standardised but that ordinary people also thought the Winchester was ripping them off because it was smaller. 

Back in the Keswick tunnel

 We were back in the tunnel on the Keswick to Threlkeld track. I was able to notice that there are echoes this close to the end. I wondered whether it was the cladding but it did seem to be the same even into the brick section.

However, as reported previously, the mid-section was acoustically dead. So is it an end effect? Is it an echo more from the change in acoustic impedance rather than from the walls?

Modes of oscillation of tractor aerials

 

The tractor pulling this trailer had two very flexible long radio aerials that showed two modes of oscillation. The first was the waving backwards and forwards from the base, like a tree in the wind. I'd have said the time period was roughly 1 second. The second mode seemed to be the third harmonic - so that there were two discernible nodes dividing the length by three. This would make the frequency 3Hz and thus the time period to be 1/3 of a second. I tried to count oscillations in 10 seconds but it was too quick, suggesting that the estimate for time period is probably correct.

A natural magnifying glass

 

Look how well these rain droplets are magnifying the cells on the back of the leaf. The droplets are vaguely lens shaped. That said, there is no distance at all from object to lens so it would make drawing the ray diagram difficult.

Light Water at Bannisdale

 

This is the bridge over Light Water at Bannisdale near Kendal. There's supposed to be a parking place here but it was coned off when we went. There is better parking just off the A6 at 545013. The use of Water as a stream name is not common in the Lake District; it is used in the south of Scotland. However, it got us thinking: Light Water as opposed to heavy water. Heavy water is water where the hydrogen is the isotope deuterium - ie the hydrogen nucleus contains a neutron as well as a proton. I was amazed to discover that the concept of light water does indeed exist - it is called deuterium-depleted water. It turns out that ordinary water contains a very small amount of deuterium and any water with less than this naturally occurring amount can be called light water.