jarvist

No, the wind analysis was not reasonable for the time - he used data from a previous generation of turbines (and in turn, the next generation of turbines were certain to be 40% bigger & etc.), from a wind farm that had quite flukey winds.

I saw him present 18 years ago, and asked him why: he said that he didn't want to rely on any predictions or models, but only discuss real data. Which is sort of defendable as a position, but ignored the fact that renewable energy was progressing so incredibly fast, and that these engineering predictions were not speculative but very much concrete.

Similarly the silicon solar panel industry in 2008 had a roadmap to get to £1/Wp over the next few years (which they did, and which led to the ~2012 explosion in solar installations), by mass producing the 'expensive' ~20% efficient (mono-crystalline silicon) technology. Mackay uses a 10% figure throughout.

So overall this was a bit like making predictions in the year 2000 assuming everyone will be stuck on 56k dial-up forever, because most people are on 56k dial-up.

These biases are present in all of the discussion of renewable technology, yet nuclear gets a free-ride / magical thinking in terms of uranium extraction, waste disposal and cleanup. And then there is the persistent obsession with land use in the book.

This led me to the conclusion (which I still hold) that this was an example of the tail wagging the dog: David MacKay wanted the 'obvious' physicists answer of nuclear power to be the natural conclusion, and by construction made it so in his book. Just because you are a Bayesian does not mean that you are unbiased!

David MacKay was an amazing scientist, but I do not think this book is accurate (even for its time), or that useful in public understanding of what we now call 'Net Zero'. It certainly popularised the idea of actually thinking through individual energy budgets, which can only be a good thing, but it was a massive missed opportunity to treat heat (chemical) energy (maximum entropy) and electrical (which can directly do work) as equivalent, just because they have the same unit.

Later on, as the 'Climate Tsar' he made a web app where you could play with the future balance of generation with a simulated model of the UK, and set your own costs for the different technologies, which I thought was much more useful. You could choose your own energy mix, and understand some of the tradeoffs.

And yes, very sad that he died so young. In the context of this book it would have been interesting to see how he dealt with the increasing mismatch of reality and his predictions as time passed.

I dunno, I flew UK-IRL this summer and in both directions I just threaded the baby-belt (standard issue here, the cabin crew hand them out before the safety briefing) around the carrier and the sleeping baby.

In a full on crash situation infants are not going to do well, so optimising for much more likely turbulence injuries (for which having the baby strapped as securely as possible is definitely a good idea!) seems more important.

These approaches always measure the wrong thing though - the average carbon cost of electricity.

What you need to know is the marginal carbon cost, which will be much less variable as almost all dispatchable generation is fossil.

So yes, you should avoiding adding load when there is a severe supply crunch and the marginal power is generated by gas peaker plants (often gas turbine based), and use power when renewable generation is otherwise being curtailed, but most of the time the grid is firmly in the middle regime with a fairly average marginal cost.

The statement that electric pressure cookers measure pressure absolutely (i.e. not relative to local pressure) was news to me, and definitely a good hack to know if you're living at altitude.

For my textbooks, I use little record cards. I write the book reference on the top line, then whatever notes or quotations etc. If it's a heavily referred to book, I sometimes use different colour cards to mean different things.

When I return the book to the library etc., I take all my record cards out and put them in a little perspex index box.

Sometimes I use the record cards to then start some more detailed notes in a notebook; sometimes the record cards refer to a page in my notebooks where I've attempted a derivation etc.

I've always had watch history off, but my searches now return a couple of pages of short form nonsense, before my actual results.

What do you not like about Feynman's "little arrows" / rotating clock hands in the QED book? I can't think of a more simple metaphor for the exponential of a complex phase, exp(i omega t). I suppose you could try and do it with more commonplace trigonometric functions, but then you lose the simple vector interpretation of adding the contributions. Or are you arguing that you should always try and teach complex numbers and the Euler identity to avoid strained analogies?

That's great! Their motivation & updates seem very sensible. Calculus Made Easy is a very nice compact book for university students who have started to forgot their high school training, and I will certainly point people in the direction of this project.

Water is incredibly efficient at transmitting sound.

The mug will attenuate almost all the signal. Maybe try with a disposable plastic cup?

This is super useful to know about! The sprite designer & waveform editor / tracker is a really good creative introduction to computers for small children. And you can jump straight in to doing this with the above web link.

(For those new to Pico-8, hit 'esc' from the Lua console to bring up the editor tools, then click on the icon in the top right.)

But it is theatre. A single £0.01 Zener diode can generate vastly more guaranteed (by quantum mechanics!) randomness, without all the possibility of failure, entropy leaking etc.