Meerkats and Infra-red at the Safari Zoo

Here at the Meerkats at the zoo in Dalton. There's an infra-red lamp to keep them warm. Why does infra-red feel warm? Try Googling that question - it's quite a controversial topic. Perhaps it is because we absorb more at that wavelength. My pale skin is obviously not a classic absorber at visible wavelengths but we don't know what "colour" it would appear at infra-red.

Vapour trail shadows on Little Hart Crag

I posted before about this topic in August and was unclear about what had caused the darkened lines on the clouds. Yesterday it was obvious. The shadow even moved from the right of the Sun to the left of the Sun as the clouds blew. But looking at the top picture, the vapour trail must have been much higher than the alto-cumulus layer than it seemed. There was an equal angle subtended between Sun and vapour trail and vapour trail and shadow. It was about 5 degrees.

Testing gravity in Dovedale

We tested gravity on the way down from Dove Crag. The question was whether a heavier stone would fall faster than a lighter stone. So let's test it. The answer is that they hit the ground at the same time. You can explain it like this: Take two smaller equal sized stones and drop them. They are bound to hit the ground at the same time. Drop them right next to each other. It won't change anything. Now glue them together. They won't suddenly fall twice as fast because you have one block that is twice as heavy. You can split any large block into equal sized smaller blocks and work the process backwards. And this is what we do. We define gravitational field strength as the pull on a 1 kg block. It is force per unit mass. It is the PER that is important. Big blocks are made of smaller blocks but gravity acts PER 1kg block so all blocks fall at the same rate.

h rho g at Glencoyne Dam

Glencoyne is the most wonderful hanging valley above Ullswater. It clearly had a mining past. This dam is in the valley floor. It must have had an earth filling. I've never seen a drystone wall dam before. The height of the dam must have been about 2 metres in the middle. Pressure in a liquid is directly proportional to depth (or height h of water above me). Pressure = h.rho.g where rho is the density of water - 1000 kg per cubic metre. g is the gravitational field strength, 10 newtons per kig on Earth. So water pressure = 2 x 1000 x 10 = 20000 newtons per square metre. That's like 2 tonnes on 1 square metre or a car balanced on a square metre. A car wouldn't go through a double wall filled with earth.

Temperature inversion on the Solway

It was a clear night last night. We could see the cosmos, which has an average temperature of around 3 Kelvin. As such, it emits very little black-body electromagnetic radiation. The Earth's surface is much warmer at maybe 280 Kelvin so it radiates more. The net effect is that thermal energy is lost from the surface of the Earth. The air next to the surface becomes cold enough for water vapour to condense and a layer of mist forms. The upper atmosphere receives thermal radiation from the Sun first and will be at a higher temperature so the mist seems trapped at ground level. Normally the air temperature is warmer at ground level and lower higher up. This is the other way round: a temperature inversion.

Fibonacci pine cones in Wreay church

I first heard about the Fibonacci Series and the Golden Ratio years ago. I've never bothered to look into it. The Series is explained here https://en.wikipedia.org/wiki/Fibonacci_number The pine cone's relation to all of the this is to do with the spirals. It is explained here https://realworldmathematics.wordpress.com/biology/plants/

Coanda Effect and the toilet at Watchtree Nature Reserve

The Coanda Effect is that a jet of fluid stays close to a convex or almost flat surface if it flows next to it due to pressure differences caused. In the case of this toilet, the set up means that a jet of urine stays close to the outside wall of the toilet and is separated from the solid waste, allowing the solid waste to be composted. There's an animated diagram at the bottom of this page http://natsol.co.uk/urine-diverting-compost-toilets/ This article on the Coanda Effect as applied to air flow suggests some experiments for me to try https://en.wikipedia.org/wiki/Coand%C4%83_effect