Putting numbers to colours

 I have become interested in the naming of colours in nature, having found out about Werner's Nomenclature of Colour. Then I found out that computers assign values to colour based on amounts of RGB. It turns out that Microsoft Paint will do the job using its Colour Picker. I tried 3 different greens in the same photograph of the fern Polypody. Clearly the light affects the perceived colour.

Playing with the phone camera settings

I had a tip off that it might be possible to adjust the exposure time on a smartphone. Research told me that for Huawei I needed settings called Pro. I found that the maximum exposure time is 8 seconds. I pressed the camera against the double-glazed window to keep it still. I was amazed to see how much light in the dark sky was being picked up. It also seems to have picked up reflected light that I think must be coming back to the lens from the outer glazing. I will now need to wait for the clouds to part so I can find out if it is possible to photograph the stars.

Circumzenithal arc

After the snow flurry we were left with this sight. This article tells you all you need to know. There were clearly ice crystals of a particular type high up. I need to try the experiment mentioned in the article.
 

Fog bow

 

I have seen and posted about fog bows before but this one caught me by surprise. There was no fog. Reading this article, I now know that I was seeing the red at the top and the blue at the bottom. It suggests that the water vapour that was in the air was of tiny size and this caused diffraction so that all the middle colours ended up in the same direction and thus appeared white to me. At the time of viewing, there were dark clouds over Scotland and a hour later we were enveloped by a cloud front that dropped a small amount of snow on us.

Does the wind make a sound if there's no one there?

It occurred to me whilst thinking about the sound of the wind in the trees that the wind only makes a sound because it interacts with objects. I hear it because the wind passes round me and over my ears. I think that any instrument placed to detect the sound of the wind will make the sound of the wind happen. Not provable by my own hypothesis, but I think that in the high atmosphere where there is nothing to hit that there will be no sound, unless the turbulence causes mechanical vibrations that end up as sound.

Testing my audio

 It occurred to me to test the audio response of the system I used to analyse the trees - which was to shoot video on an old ipod and play it through the laptop speakers into Audacity. This time I shot video of tones generated in Audacity to see what happened. First is 1000Hz. It clearly peaks there but there is some white noise behind.

Next was 10000Hz. The peak is in the correct place but notice that the decibels are so much lower. The white noise on both seems to be about -80dB.

As an experiment I tried the highest available tone of 22000Hz. I can't hear that. Neither can the microphone. This might look loud but it is all below -73dB so it is just the same white noise. It seems the analysis of the tree might be correct because though quiet, it reached -33dB.

Solar batteries

 

A lot of houses now have solar panels on the roof. I had always assumed that this was for feed in to the National Grid but I heard about solar batteries for the first time last year. Turns out it is basically having something like an electric car battery eg Tesla which is charged from your solar panels so that you can use the electricity generated at other times. This must be because of the advances in battery technology in the car industry. This site outlines some of the parameters. A quoted value of 6kWh would be good because that roughly the amount we are using at the moment. What seems to be lacking is how long it might typically take to recharge, especially at this time of year. Another disadvantage is that it seems most won't supply energy to your house during a power cut.