Blue light on the coral

At the aquarium we were shown blue light shining onto the coral. 

Apparently this coral obtains most of its energy by having a symbiosis with a unicellular organism which does photosynthesis, hence the need for light. I asked about why blue light. I was told that the photosynthesis would work in white light but that the blue light is used so that the green colour is very clear. There was ambient white light from the room as well that gets in through the front of the tank. Perhaps it is the reflection of part of this that I was seeing in the green colour because in colour theory, surely shining blue onto green should look black. Or else the blue covered a vast slab of wavelengths that included green.

Lots of Teslas

I used to park in the car park near this research facility and was always happy to see the signs warning about high magnetic fields. The unit for magnetic field strength is the Tesla. I suppose these days younger students will think it's named after the cars. Teslas always seemed like a mis-sized unit. So one of the strongest magnets there is has reached 11.7 Teslas. It's like capacitance in that most values you come across are milli and micro.

Lunar New Year

I was intrigued by this card. I was wondering how you would decide when to start a year in a lunar calendar. If you follow a strictly lunar calendar, then the months don't tie in with the solar calendar we use. So Ramadan occurs in different western seasons as the years go by. The answer to this Lunar New Year is that it is not truly lunar. It is called a lunisolar calendar where a "leap month" is put in every now and then to make the same festivals come up at the same point relative to the sun every year. This is called intercalation.

Nannycatch

The Nannycatch Valley is an impressive, steep sided gorge. I have read that it was formed at the end of the Ice Age when glacial meltwater was dammed. When it burst through, the wild surge of water carved the valley. I can't find a reference to it on the Internet amid the walking routes. It must have been in a book so I need to search out that reference. The force of the water must have been immense.

Work done to put a stone on Dent

This stone on Dent is obviously a glacial erratic and lots like the Ennerdale Granophyre. You can see the origin in the distance up to 10km away. My poles are 1.4m long so the stone is approximately 1m x 1m x 0.5m = 0.5 cubic metres. The rock gas a density of say 3000 kg/m^3 to 1sf. Mass of rock = 1500kg. Weight of rock = approx 15000N. Now if I wanted to calculate the work done by the glacier moving the stone 10km, which force would I use? Could I say that the work has been done against gravity holding the stone up? Or is it work done against friction? And if so, is that friction under the stone, which might be held fast anyway, or friction under the glacier? Can't resolve this at the moment.

You've got potential

 

Potential is such a wonderful physics word. I used to say that if I wrote on a report "this student has potential" then it wasn't a good thing. It would mean you'd got the ability but weren't using it.

Interesting diffraction rainbow

I noticed the rainbow to the right of the mug. It is not correct for a CD reflection grating which should be a radial pattern.

Then I edged the mug round a bit and realised it was diffracting the light reflected from the curved white mug handle.