Wigton church clock and escapement

This is the clock mechanism is the tower at Wigton. One issue that had always concerned me was that a pendulum always loses energy as it swings and yet pendulum clocks just keep going. I know that you wind up a clock to give it energy - I have wound up this clock; it's hard going! But I wasn't clear how this happens. It's the toothed gear wheels that do it. The mechanism is called an escapement. I'll do a future post to explain how our clock is given energy by winding up weights. However, as far as I can see, the force from the springs pushes on the pendulum by means of the gear wheels of the escapement.

 

Here is the lever from the clock mechanism to the pendulum.

 

Then the swing of the pendulum regulates the speed at which the gear wheel can rotate, thus fixing the speed at which the clock ticks.

Hydro-electricity on the bird reserve

We visited Loch Ken in southern Scotland. It's 9 miles long and part of it is a bird reserve.

 

 

A display board on the reserve explained that the loch was created by damming in 1937.

 

The dam actually looked more like a weir. I seemed to be possible to raise and lower it. You'll have to look hard to spot the top of the structure in this picture. The display board said that the actual power station fed by the loch is at Tongland. This is quite a few miles away. Wikipedia says that it is part of the Galloway Hydro scheme from the 1930s. They did it then because the National Grid had just been invented. Before that, all electricity generation was local; every town had its own power station and there would not have been the population to justify a scheme like this in Galloway. The power station is quoted at 33MW and it says that the water falls 106 feet. It also claims that these power stations were some of the least costly ever built in terms of £ per kW. http://en.wikipedia.org/wiki/Galloway_Hydro_Electric_Scheme

Close-packed bubbles

 

I found these bubbles in a stream near Coniston. They reminded me of the way atoms are packed together in materials. I think this is the hexagonal close packed model. The large bubble is similar to the way that large carbon particles stick out between the layers of iron atoms when you make steel, stopping the layers sliding over each other and turning a brittle material into a ductile one.

The power of the sea at St Bees

 We went to St Bees. We had seen TV coverage of the tidal surge earlier in the week. The grass above the promenade was covered in stones and debris. All of the life belt holders had been knocked flat. I did some calculations of the force of the wind hitting me in a December blog post. The theory says that the rate of change of momentum of the water hitting the life belt holder is the same as the force of the water. The assumption made is that the water stops dead. The theory is on the earlier post. I estimate that the life belt holder is 75 cm square. I'll estimate that the sea is doing 10 mph, which is 4.4 metres per second. The volume of water stopped in one second = area x speed. Change in momentum = mass x speed = density x volume x speed = density x area x speed squared. I get 11kN which is the equivalent of 1 metric tonne hitting the red board. If I could remember the bending moment theory I learned at university, I could calculate the minimum force from the fact that the steel bent at the bottom and thus tell you the minimum speed of the sea water. Trouble is that even a bit of Internet research isn't bringing it back quickly enough.

 

We are fond of the café and it has taken a bit of a pounding too. The banks below it don't look too secure.

 

Stargazing Live

 

We went to the Stargazing Live event in Cockermouth this evening. Thanks to the Astronomical Society people who put it on. I'm jealous of the auto-steer devices on some of the telescopes. My wildlife telescope can see as well as some of the smaller astronomical ones but it's very difficult to find a small point of light in a dark sky using mine. However, I did take this picture of the Moon. China landed the first lunar probe for nearly 40 years last month. I've labelled the landing site of Chang'e 3 on the picture below. Sorry it didn't come out too well.

 

 

Spring in Coniston

I found this playground toy. When I sat on it and rocked backwards and forwards, the time period was about 3 seconds.

 

 

With no one on, the time period was less than a second.

 

I'd hoped that perhaps it could be modelled as an inverted pendulum but clearly not. There will be an elastic restoring force when it is displaced. I'd have to go back to my degree work to remember how to calculate that and thus figure out if the motion can approximate to simple harmonic motion.

Solar power again

We went to the RSPB nature reserve at Leighton Moss. Here's their solar panel display. I last posted about this in December 2009. Then they had generated 8749 kWh of energy. So in 4 years and one month they have generated an extra 5557 kWh. That's about 1490 days. Assuming an average of 12 hours daylight every day that means 17892 hours and thus an average of 0.3 kW being generated. 300W is not much but I forgot to see how big the roof panel area was. That said, at say 10p a unit, it is £500 of electricity.

 

 

 

By the time we left the café it said it was generating 0 kW. This is the light level that generates no solar electricity ...