Christmas Break

Friends, it’s been a busy year, and I’m going to take break from blogging for a week or so.

I am really grateful to everyone who reads this blog. I would probably be writing it whether or not you were reading it because writing helps me to clarify my thoughts. But I find the idea that anyone reads what I have written very moving.

So, thank you, and best wishes to you and yours for 2023.


The other day I clicked back through the 920 articles I have written since 2008 and came across this slightly chaotic video of a talk I gave at NPL in 2017 on the physics of candles.

And re-watching it I was amused and distracted, and so I thought I would re-post it in case you too might be amused or distracted!

Candles really are astounding! For example:

  • Did you know that wax in bulk is not flammable?
  • Did you know the temperature of a candle flame?
  • Did you know that a candle stores 8 times more energy than a stick of dynamite?

If would like to access some of the fancy PowerPoint™ animations you can download the PowerPoint file here.

The highlight of the talk is using a candle to power a thermo-electric generator, which in turn powers a USB port, which in turn powers a torch, which is brighter than the candle.


And by the way, here is the slow-motion candle-relighting movie that is embedded in the PowerPoint but which doesn’t show up well in the lecture theatre view.

Thanks again to Brian Madzima for the videography and editing, and Nikita Mezhnyakov for the photograph.


8 Responses to “Christmas Break”

  1. Simon Says:

    I am delighted to say I had the pleasure of attending a live version of this (perhaps this very) talk, and it stays with me.
    Thanks, and Merry Christmas, etc

  2. Ian Nicholson Says:

    Candles are great and something I often wax lyrical about. I lit one yesterday in a Catholic church I called into whilst walking.
    Merry Xmas to you and yours.

  3. David Cawkwell Says:

    Amazing a non flammable sustance that burns. I never thought of that. You can also use the paraffin wax latent heat for heat storage having a melting point of 60 degrees.

  4. Neil Kitching Says:

    Hello Thank you, I am enjoying your blogs as I have gone all electric. A question for you on solar panels. I had some fitted recently, 4 on a SE facing roof, 2 on a SW facing roof. They are fitted with a single string inverter. Is this sensible? I am worried that I will not be maximising the output because the sun rarely shines on all the panels at the same time. Not sure whether to complain to my installer. Neil

    • protonsforbreakfast Says:

      Neil, Good Afternoon,

      “Is it sensible?”. At first it would seem obvious that each group of panels should have its own dedicated string. But the word on The Web seems to be that it is not so clear cut. Take a look at this video from “Gary does Solar”. It’s very methodical and indicates a single string with one or two shaped panels generally does much better than one might initially fear.

      The reason is that modern panels all have “bypass diodes”. In a single string, every individual cell within a panel and within a whole string is in series: the same current (~10 amperes in full sunshine) flows through all of them. If even one cell is shaded it has a high resistance and reduces the current in all the cells in every panel. However, when the voltage across a group of cells gets too high, a bypass diode is activated and the shaded cells are isolated.

      If the panels are new I would suggest you monitor it for a year and see if the generation is anything like your installer led you to expect.

      Year-to-Year variability of solar output is around ±10% so if the system gives less than 90% of what the installer suggested, you might take that up with them. If they are MCS accredited, they will need to respond seriously.

      On the plus side, the solar will be just better and better for the next six months!

      All the best


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