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.

Using rubber ducks to map ocean currents

We found a rubber duck on the sands at Grune Point. It reminded me of the way that a spill of 28000 plastic bath toys into the Pacific Ocean in 1992 led to the mapping of ocean currents. See here for details. Our duck was not one of them - ours was from Poundland but looks like it's been in the sea a while. It is now adapting to its new home in Wigton! 
 

More sound of the wind in the trees

 

I got a better recording of the strong winds on Saturday night blowing through the poplars. This time I managed to get section that didn't involve the bit where the wind was hitting the phone microphone. The peak this time is sharper and closer to 300Hz. This is only due to branches. I stood near the shrubs later and there was a different sound due to leaves rustling and hitting each other. I am also wondering whether the microphone range might be a factor but this suggests not. But I do have ideas about how to test this.

Olber's Paradox at Watchtree

Looking into the trees in Pond Wood, it isn't possible to see beyond. There are trees in every direction. This made me think of Olber's Paradox. This says that if the Universe is infinite, there should be a star in every direction and therefore the sky should be white. The sky is black so the Universe cannot be infinite. These days I think that is taken to mean it is finite in time because the distance we can see is determined by long the light has had to travel.

Compostable plastic

 

I was interested in this clue about standards for compostable plastic. Some thoughts on the standard are here. Scrolling down on this, you'll see that temperature is an issue, and perhaps volume. The bag shown has been on my desk for some weeks and has not decayed. It seems that the thing is to have a warm compost bin. Also that industrial and home composting are two different things. One method seems to involve having plastic-digesting enzymes encased in shells that break down at the higher temperatures, releasing the enzymes. This Guardian article is sceptical about whether it can work.

Space batteries from Cumbria

 

This article in the local paper alerted me to something I didn't know. I knew that radioactivity was used to power space craft but I didn't know how. Turns out it is called an RTG and works by bolting one end of a thermocouple to the container for a radioisotope. The other end of the thermocouple is bolted to a heat sink. A lot of outer space is very, very cold away from direct sunlight so there will be a big temperature difference from the warmth coming from the radioactive decay products. The thermocouple generates electricity from the temperature difference. Maybe "generates" isn't the right term to use here. I'll think about that. The Wikipedia page has a wonderful assessment of the pros and cons of Americium-241 vs Plutonium-238.

The sound of the wind in the trees

 

A strong wind is blowing today. The sound of the wind in the tall trees is like the sound of the waves on the shore. I did an analysis a few years ago of whether the wind blowing past a wire caused the wire to oscillate like a string on a guitar and thus make a sound. The calculated frequency was so far out that it isn't that. Then I found out about Aeolian harps. The effect is due to vortex shedding. I think that is likely too for these bare tree branches. I recorded the sound and played it into Audacity. Here is the frequency spectrum.

It is certainly not the spectrum for any of the types of noise I posted about a couple of months ago. It peaks at 200Hz. I am now wondering if different types of tree have different spectra.

Rain drop components

It rained very heavily all the way to London. I noticed the consistent angle of all the rain down the window on the motorway. If we were stationary in still air I would expect the rain drop trails to be vertical. At 60mph they were at a large angle to the vertical. I thought the angle would decrease when we slowed down in the city but that didn't seem to happen. I wonder if there is some sort of effect that once tracks get set across the glass, they become lines of least resistance that the water follows thereafter. More observations needed.
 

Experience Real Sound!

 

Mrs B pointed this one out to me. I don't know what to make of it. I think it refers to vinyl records and I suppose these do start with mechanical vibrations in a groove but these are then converted into an electrical signal. Is it analogue that they consider real? If we hear it as a sound, it is a real sound. Ultrasound is interesting. It really is a mechanical vibration but we often experience it in a visual form. So a cool advertising slogan and lots to think about!

Milton Keynes grid road system

 It took a while for the penny to drop that with roads labelled V4, V5, V6 etc heading roughly north and roads labelled H2, H3 etc heading roughly east, the road grid was set up like Cartesian axes with horizontal and vertical. There's a big article about it all here. Whilst it is good to have such fast roads with no interruption, I found this very rational scientific system harder than expected to navigate because so much seems the same that we lost our bearings at times. We did find the concrete cows though!

Wave motion in the lights

 This was a nice visual effect. The eye is drawn to follow the pattern upwards but it is only the pattern that is moving. The lights stay fixed and are either on or off. It is such a brilliant example of what constitutes wave motion.

Closed system in Kennington

The amazing Christmas lights in Kennington were better than ever.

I really liked the polystyrene snow effects in the old street lanterns. I realised that it is not possible for the figures to ever get buried because each is a closed system. A pump takes beads from the bottom and pumps them round to the top where they fall.

Even better for a physicist, this process also charges the polystyrene so some of the beads are attracted to the inside of the plastic moulding.

 

Lensing effect of a water jug

Look at how clear the bubbles in the water are on this edge. Notice also that you can't see the table cloth pattern on this edge. The beveled edge creates a lens shape that is focusing the light to some extent.